Chapter 18 - Dietary Treatment of Obesity Johanna T. Dwyer, DSc, RDProfessor of Medicine and Community Health and Professor of Nutrition, Senior Scientist Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University,Box 783 Frances Stern Nutrition Center, Tufts Medical Center, 800 Washington Street, Boston, MA 02111 jdwyer1@tuftsmedicalcenter.org Kathleen Melanson, PhD, RD, LD Associate Professor; Director, Energy Metabolism Laboratory at University of Rhode Island, University of Rhode Island, Department of Nutrition and Food Sciences 112 Ranger Hall, Kingston, RI 02881 kmelanson@uri.edu Corinne Dobbas, MS, RD Tufts University Medical Center, cdobbas@gmail.com Lindsey Toth, MS, RD, Tufts University/Tufts Medical Center’ Lindsey.Toth@gmail.com With the assistance of Lisa N. Faucon, MS, RD, Assistant Director Nutrition Services at Kaiser Permanente, 4647 Zion Ave, San Diego, CA 92120, lisa.n.faucon@kp.org TO OBTAIN A DOWNLOAD OF THIS CHAPTER IN WORD OR PDF FORMAT, CLICK HERE	Contents Contributors Search

1. Introduction

NHANES data reveals that over 30% of adults in the United States today are obese (1). Obesity is a chronic medical condition that requires long-term therapy (2-4). If left untreated, overweight and obesity increase the risk of serious diseases, such as diabetes, hypertension, dyslipidemia, coronary artery disease, and metabolic syndrome, among others. In addition to its accompanying comorbidities, obesity can engender myriad of negative psychological effects, and can have a diminishing effect on one’s overall quality of life (5).

Self-initiated approaches to weight reduction are often ineffective. People frequently believe that there is a quick and easy remedy for curing obesity, when in fact, there is no easy way. The only way to keep off excess weight is through life-long obesity prevention involving physical activity, balanced with a healthy diet (2;4).Health professionals can help people become more effective at maintaining a healthy weight, or losing weight if this is necessary.

Health professionals often ignore treating obesity because they regard it as being unlikely to improve with usual therapy. However, a modest (10%) weight reduction in obese people is an attainable goal, and often results in clinical improvements of several health-related parameters, even if the individual remains clinically obese (2;6;7). This information should encourage health professionals and patients that they need not be overwhelmed by their inability to meet excessively ambitious, or unrealistic, weight loss goals (6;8). Smaller weight losses can still bring considerable health and social benefits.

There is a great deal of misinformation about obesity in many countries today, including the USA. According to a survey by the Natural Marketing Institute, 59% of the general population would benefit from losing weight. Of them, 26% used weight loss products in the past year, 21% used prescriptions, 18% used over the counter medications and 11% used weight loss dietary supplements to maintain and/or manage their weight (9). Only some of these strategies are effective, as we will see in this chapter.

Weight management counseling of overweight and obese patients deserves reconsideration and reemphasis by health professionals because it carries such a great potential for health benefits. Obese patients receiving weight reduction advice from their physicians are significantly more likely to embark on weight loss attempts than those who do not. Yet less than 42% of obese individuals reported that they received weight loss recommendations from their physicians (10). These findings underscore the need for increased physician and health professional involvement in obesity treatment (3;8;11). When physicians are appropriately aware of and include recommendations for lifestyle changes in counseling their obese patients, results are promising (10;12). Even more importantly, they should stress achievement and maintenance of a healthy weight before obesity becomes apparent.

The 2005 Dietary Guidelines for Americans (Table 1) provides assistance in maintaining and achieving a healthy weight and eating pattern as well as reducing risk of chronic diet-related diseases and promoting health (13). MyPyramid.gov(Figure 1) and the Dietary Approaches to Stop Hypertension (DASH) recommendations (Table 2) also provide specific guidance on food selection to assure a healthful diet. The 2008 Physical Activity Guidelines for Americans also provide science-based guidance to help Americans, ages six and older, to improve their health through the appropriate forms of physical activity (Table 3). These guidelines are all useful for weight maintenance. For the weight loss phase of weight control, additional measures are necessary and are discussed in this chapter.

This chapter, briefly reviews steps health professionals can take to help their patients manage their weights more effectively, and to reduce weight by dietary means when necessary.

2. Rationale for Dietary Treatment

Two-thirds of adults in the United States are currently overweight or obese. The percent of overweight and obese people has risen to this point over the past several decades, among men and women, all ethnic groups, all ages, and all education levels. From 1960 to 2004, the prevalence of overweight in the United States increased dramatically, going from 45% to 66% in adults ages 20 to 74. The prevalence of obesity in the United States also grew, more than doubling from 13% to 32% (17). In recent years the trend has slowed, but not stopped, indicating that attention to weight control and maintenance are not matters that should be confined to those who already are overweight.

Weight control has health advantages, and therefore maintaining or achieving a healthy weight is important for all Americans. Obesity is associated with an increase in mortality rates. Obese individuals have a 10 to 50% increased risk of death depending on the degree of obesity from all causes when compared with healthy weight individuals (17). In weight control, an “ounce of prevention is worth a pound of a cure,” because once weight and fatness have surpassed healthy levels, they are difficult to reduce. Therefore, it is important for health professionals to monitor the weights of all their patients and to provide anticipatory guidance so that those who are already at healthy weights remain so. The 2005 Dietary Guidelines for Americans (Table 1) stress maintenance of a body weight within a healthy range by balancing calories from foods and beverages with calories expended, by preventing gradual weight gain over time, by making small decreases in foods and beverages, and by increasing physical activity. However, this is easier said than done. The chapter will assist health professionals in operationalizing these recommendations.

3. Evaluating Overweight and Obesity

This section outlines a stepwise approach for assessing overweight and obesity.

3.1 Assess Body Fat Burden and Health Status

Before any patient is placed on a reducing diet, medical assessment of his weight, fat distribution, and health risks is essential.

3.2 Measure Body Mass Index (BMI) as an Indirect Measure of Body Fat Burden

Weight should be measured, without clothing, on electronic scales, which provide accurate weights even for heavy patients. Height is best measured with a wall-mounted stadiometer or against a wall rather than on beam-balance scales, which are unsteady and unreliable. Body fat is difficult to measure directly in clinical practice. Body mass index (BMI), provides a better measure of fatness than weight alone, and can be calculated using the following formulas (2).

BMI= (weight lbs x 703) ÷ height in inches² or BMI = weight kilograms ÷ height in meters(3)

Assessment of BMI and tracking weight changes are two simple means of monitoring weight. An increase of more than 1 BMI unit (which is about 10-14 pounds depending on height and weight) signals the need for instituting preventive measures.

Table 4presents the National Institutes of Health (NIH) classification of BMI values for adults (2). These values are based on abundant data associating higher BMI levels with higher health risks. Although individuals with the same BMI often differ somewhat in the amount of body fat they have, this is still a useful approximation that can be performed quickly and inexpensively.

Individuals with a BMI under 18.5 are classified as underweight, whereas those with a BMI over 25 are considered overweight; those over BMI 30 are classified as class 1 obesity, those over BMI 35 as class 2 obesity, and those over BMI 40 as extreme, or class 3, obesity. In general, the orthopedic and metabolic hazards increase with increasing BMI.

3.3 Measure Waist Circumference to Quantify Risks Related to Body Fat Distribution

The distribution of fat on the body, as well as its sheer amount, also alters risk. The reasons for this are becoming clear as the role of adipose tissue as an endocrine organ is more fully understood. Excess abdominal fat in the viscera, characterized by an accumulation of fat centrally (sometimes referred to as android "apple" or abdominal fat distribution) is associated with greater risk of certain chronic degenerative diseases than is a peripheral fat deposition pattern (gynoid "pear" or lower body fat pattern).

Although the causal associations between certain diseases and body fat distribution are still a matter of debate in the scientific literature (18;19), measuring waist circumference in addition to BMI is still clinically useful in assessing risk posed by body fat distribution (2;4;20-22).

Visceral and subcutaneous fat are difficult to measure in office practice. Waist circumference, taken at the level of the umbilicus (belly button) with a plastic or other type of non-stretchable measuring tape, is a reasonable proxy for assessing the likely size of visceral fat deposits and the extent of abdominal obesity. Waist circumference is easier to measure and more straightforward to interpret than waist-to-hip ratios. It is being increasingly used as the standard in assessing central vs. peripheral fatness. The cut-points for increased risk are a waist circumference of greater than 35 inches in women, or greater than 40 inches in men (2). Although the usefulness of these absolute cut-offs have been questioned due to the many possible confounding variables in their relationship with health, monitoring changes over time is still advocated (23). Table 5shows how risks of weight related conditions such as type 2 diabetes, hypertension, and cardiovascular disease increase with greater BMI and waist circumference. Patients with high waist circumference may need increased monitoring and treatment of blood pressure, blood cholesterol, and other cardiovascular risk factors. Physical inactivity and smoking increase health risk still further. They act synergistically. They apparently increase the severity of the other risk factors present as well as increasing risks themselves in other ways. Elevated serum triglycerides are another marker for increased cardiovascular risk that increases with high waist circumference.

3.4 Document Other Risk Factors and Comorbidities That Increase Risk and Have Other Implications for Therapy

The presence of risk factors or clinically evident diseases further increases the health risk of obesity over that evident with high BMI and high waist circumference. Table 6describes different conditions that further add to the adverse health effects of the obesity itself. There are also problems that must be managed with other modalities in addition to weight control. Weight loss can help lower elevated blood pressure, blood glucose, both total and low density lipoprotein levels (LDL), plasma cholesterol and triglyceride levels, and raise high density lipoprotein (HDL) cholesterol levels in those with abnormally high values. Pharmacologic therapy may also be necessary to bring some patients into healthy ranges.

3.5 Determine if the Patient is a Candidate for Weight Loss

All individuals with a BMI over 25, and those at lower BMIs with a high waist circumference and two or more of the risk factors listed in Table 6, are potential candidates for weight reduction. The goal of weight control is both the reduction of weight and the maintenance of healthy body weight over the long term. If this is impossible, at least prevention of further weight gain should be attempted. Those with a very high BMI (over 35) are unlikely to be able to achieve sufficient fat loss on a usual low calorie diet of 1,200 to 1,500 calories without regimes that continue for many months. They should be referred for care to a multidisciplinary team specializing in obesity for treatment with very low calorie diets and possibly surgery.

Some individuals whose weights are at healthy levels and who are without weight associated health problems also may wish to lose weight. These few need to have their concerns about diet addressed, but should not embark on reducing diets since there is no medical reason for them to do so. They should be discouraged about decreasing weight still further, and counseled to follow MyPyramid.gov(Figure 1), the Dietary Approaches to Stop Hypertension (DASH) eating plan (Table 2), or the Dietary Guidelines for Americans (Table 1). If excessive concern about weight continues and the patient refuses to diet, counseling may be helpful from a psychologist or psychiatrist to alleviate their concerns.

4. Choose Treatment Options

The following section covers the various means of treating obesity, including dietary changes, medications, and/or surgical options. Diet is involved in all of these options.

4.1 Assess the Patient’s Readiness and Willingness to Lose Weight

The procedures and methods described in the previous sections provide a reasonable assessment of the health risks associated with obesity and the potential health benefits accruing from weight loss. Weight control requires behavioral change, which cannot happen without patient consent and "buy-in". Therefore, the health risks of overweight and obesity need to be communicated and patient readiness needs to be ascertained.Table 7outlines the various stages of behavior change as conceptualized by Kushner using Prochaska’s research. This model of behavior change is referred to as the Transtheoretical Model of Behavior Change(5). However, many patients do not follow such a logical path to action, and may go back and forth repeatedly among other phases.

Unfortunately, those who are most concerned about their weights are not necessarily those who are at the highest health risk. Moreover, those who are at highest health risk are often unaware of how serious their problems are, or are in deep denial about them. The consequences of excess weight must therefore be raised and carefully explained. Many obese individuals may fall into this category of high risk people who are unaware of their health problems, and they must be motivated to lose weight.

Once patient readiness and willingness to lose weight has been ascertained, a plan of attack needs to be jointly devised with the patient. Some patients are ready to start a treatment program immediately, and the patient and counselor are able to begin setting goals together right away. Other patients have reservations or other issues keeping them from reaching the action stage needed to embark upon their weight loss goals, making it important for the counselor to first address these road-blocks before moving on. For patients who are not ready to act, the issue should be deferred and brought up again at the next visit, rather than dropping the subject entirely, or a referral to a registered dietitian should be provided where the subject can be addressed in depth further. Still, other groups of patients are unable or unwilling to embark on a weight reduction program at all. These patients, however, may be willing to take steps to avoid further weight gain, or may be willing to work on other risk factors such as cigarette smoking or increasing physical activity, and they should be encouraged to do so.

Normal weight patients who wish to control their weight may also ask for help in weight control. They should be counseled to avoid weight gain and should be provided with information on healthy eating and physical activity levels. Such recommendations are summarized in Table 1, in Table 2, and on the web at www.MyPyramid.gov(see Figure 1).

4.2 Decide if Dietary Treatment is the Appropriate Option

Dietary Treatment is not for everyone. Although weight reduction with dietary treatment is in order for virtually all patients with a BMI of 25-30 with comorbidities, and for all patients with a BMI over 30, a hypocaloric diet alone may not be enough to prompt significant and lasting weight loss, especially in very heavy patients (25). Moderately low calorie diets are certainly unlikely to suffice in treating those with BMI >35, as it will take these individuals a significant amount of time to reach their goals (e.g., many months or even years). Referral to a multidisciplinary obesity treatment team would be in order to provide more intensive measures if necessary (i.e., very low calorie diets, pharmacological treatment, and/or gastric bypass surgery).

4.3 Decide if Drugs will be Useful Adjunctive Therapy to the Reducing Diet

Prescription drugs may also be considered for those with a BMI 30 or more, or a BMI of 27 and above if comorbidities are present, if the patients are unable to lose weight with dietary measures alone. The addition of weight loss medication to a weight loss regimen leads to an average weight loss of about 10 pounds more than dietary measures alone (26). However, weight loss drugs are only adjuncts to, rather than substitutes for, reducing diets, and a reducing diet will still be necessary. Without a hypocaloric diet, drugs are unlikely to be effective. Table 8provides an overview of available medications for weight loss prescription. Note that none are totally free of side effects.

Most of the Food and Drug Administration (FDA)-approved weight-loss medications are approved only for short-term use (which is usually interpreted to mean use up to 12 weeks), although some physicians still prescribe them for longer periods of time(26). Only two prescription drugs are currently approved for long-term use in weight reduction: sibutramine and orlistat. Sibutramine (Meridia^TM) is an appetite suppressant that works centrally in the brain to decrease appetite. Its advantages include slightly greater net weight losses and longer maintenance of losses than diet and physical activity alone. Disadvantages include chronic increases in blood pressure in some patients and the relatively high costs for the drug (27).

Orlistat is available for both prescription (Xenical^TM) and over-the-counter at a lower dose as Alli^TM. Over-the-counter Alli^TMis available only to adults aged 18 and older, and is a half-dose version of prescription orlistat (http://www.myalli.com) (26). Both versions of the drug are to be taken three times daily, before meals (28). Orlistat operates at the level of the gut to inhibit pancreatic lipase and thus fat absorption.It increases net weight loss, at least over the short run, compared to a reducing diet alone (29). Orlistat may also foster adherence to low-fat reducing diets because of the fat malabsorption it induces. This fat malabsorption may negatively condition some patients to decrease their fat and overall caloric intakes, because over-ingestion of fat may result in anal leakage. Orlistat’s disadvantages are fat malabsorption, sometimes accompanied by anal leakage, and decreased absorption of fat-soluble vitamins. Because of this decrease in fat-soluble vitamin absorption, patients taking Orlistat should be advised to take a multivitamin supplement containing fat-soluble vitamins to ensure adequate nutritional status (30). The drug is not effective without a hypocaloric diet. Dietetic counseling is helpful in managing the weight loss, since a low-fat low-calorie diet is also necessary.

Phentermine (Obenix^TM), phendimetrazine (Adipost^TM), diethylpropion (Tenuate^TM),and benzphetamine (Didrex^TM) are modestly effective prescribed anorectic agents approved for short-term use (12 weeks in a 12 month period) by the Food and Drug Administration (FDA) (27). Phentermine and diethylpropion are widely prescribed, as they are relatively inexpensive (approximately $30 for a one-month supply), and provide slight stimulatory effects. However, little research has been done on their long-term side-effects (28).

The off-label use of bupropion (Wellbutrin^TM), a drug originally approved by the FDA for aiding in smoking cessation, has become popular in the past few years for weight control. Bupropion enhances norepinephrine and weakly blocks dopamine reuptake and is being studied for the treatment of obesity. Bupropion could be considered if a patient presenting with obesity wanted to quit smoking and lose weight (27). Short term side effects most often reported are agitation, dry mouth, insomnia, headache, nausea, constipation, and tremor. However, its long-term effects on weight loss are not clear, and its use must be accompanied by a low-calorie diet.

Topiramate (Topamax^TM) and zonisamide (Zonegran^TM) are anticonvulsantsthat were originally approved to treat epilepsy. They are also sometimes used off-label for their weight-loss effects. However, adverse effects have also been reported, most commonly difficulty with memory, parathesia, difficulty concentrating, and mood problems. These drugs are approved by the FDA for epilepsy only, and not for weight loss (26;27).

Metformin (Glucophage^TM) is a diabetes medication that may promote small amounts of weight loss in people with obesity and type 2 diabetes. Why it is that this drug works as a weight loss aide is unclear. It is hypothesized that it works by reducing hunger, and therefore food intake (26).

Byetta^TM(exenatide and pramlintide) products are sometimes used in treating the comorbidities of obesity. Both affect the gastrointestinal hormones that regulate glucose homeostasis, gastric emptying, and satiety. Exenatide (Byetta^TM) is used as an adjunctive therapy for improving glycemic control in patients with type 2 diabetes, among patients and who also take metformin or sulfonylurea. Pramlintide is an adjunctive therapy for patients with type 1 or type 2 diabetes who use insulin at mealtimes. Usually patients with diabetes gain weight with better glucose control, however, with these drugs, better blood glucose control is often associated with weight loss, at least in preliminary studies. The most common side effect of these medications is nausea (27).

Major disappointment has come with continued research on the once promising class of drugs known as cannabinoid (CB₁) receptor antagonists. Rimonabant (Acomplia^TM) was the first CB₁receptor blocker approved for use in the world. Its suggested use was for patients with a BMI of 30 or more, in conjunction with exercise and diet, to aid in weight loss. CB₁receptors are located in the brain, gastrointestinal tract, adipose tissue, heart, pituitary, and adrenal glands, and if they are stimulated, these receptors increase appetite. Blockage of these receptors is thought to decrease appetite. However, the FDA ruled that Rimonabant carried too much risk to be approved for use in the United States, with side effects including nausea, anxiety, diarrhea, and depressed mood that in severe cases, led to suicide (27). As of 2009, the European Medicines Agency (EMEA) has also concluded that the benefits of Rimonabant no longer outweighed the risks, and marketing authorization for the drug in the European Union was officially revoked (31). Investigation into the cannabinoid (CB₁) receptor antagonist class of drugs has since ceased (28).

Further research into weight management drugs continues, with new antagonists of neuro-peptide-Y (NPY), peptide-YY (PYY), oxyntomodulin, amylin, and glucagon-like peptide-1 (GLP-1) being used to induce weight loss through reduced food intake. Two specific drugs currently being studied include cetilistat (ATL-962) and tesofensine (NS2330). Cetilistat works as a lipase inhibitor, similar to orlistat, with a seemingly favorable side effect profile. Tesofensine was originally researched for the treatment of Alzheimer’s and Parkinson’s diseases, but was dropped when early trial results showed limited efficacy. The drug did however show significant weight loss among the trial participants who were obese (32). Tesofensine is a reuptake inhibitor of norepinephrine, dopamine, and serotonin, which has a dose-related weight loss response. Many companies are also beginning to experiment with combinations of the above drugs, in hopes of reducing the occurrence of adverse side effects, and enabling reduced dosages. Some of the combinations currently under development include topiramate-phentermine, bupropion-zonisamide, and bupropion-naltrexone (28). Until clinical trials of efficacy and safety considerations have been evaluated, these medications should not be prescribed.

The FDA recently released an extensive list of tainted weight loss products, many of which contain undeclared drugs (Table 9) (33). If patients are taking any of these contaminated products, they should be advised to stop immediately. Table 9provides a comprehensive list of these tainted products, along with the undeclared pharmaceutical/chemical included in the product. There are also other drugs no longer available for distribution because of adverse and sometimes fatal side effects including Fen-Phen^TM, Redux^TM, Pondimen^TM, fenfluramine, and dexfenfluramine.

Drugs for weight loss are of limited efficiency, some patients cannot afford them, and all of them have side effects. About one fourth of individuals who are prescribed medications will not have the expected response (28). Patients who are likely to respond to drugs tend to do so within the first month of therapy. If they fail to lose four pounds (1.8 kilograms) in the first four weeks, the drug is unlikely to be effective, and it may be appropriate to discontinue its use. A loss of four pounds within the first four weeks generally predicts weight loss of at least 5% body weight by six months of therapy, if the diet and drug continue to be used (28).

Dietary supplements purported to be helpful in weight loss are discussed in section 9.7.3(Dietary Supplements and Weight Loss). No supplement currently on the market is both safe and effective for weight loss.

4.4 Rule Surgical Options In or Out

Surgical options such as gastric bypass and lapband surgery are recommended only for patients classified as Obese class 3 (BMI>35) or Obese class 2 (BMI >30) with comorbidities. Patients who opt for the surgical route must adhere to certain dietary recommendations before the surgery is performed to show they are able to follow a hypocaloric diet. After surgery, food intake is altered because their gastric capacity is considerably limited (34). The post-operative weight reduction surgery diet used in one hospital is shown in Table 10, but there is no standard, widely accepted protocol for diet therapy post-bypass at present. Dietary restrictions must continue long-term after surgery, and indefinite continuation of appropriate vitamin and mineral supplementation will be needed to prevent deficiencies. Diet therapy is an important part of bariatric surgery, and one that is often ignored to the patient’s peril.

5. Set Goals

Goal setting is an important part of achieving weight loss. This section will outline the steps in goal that setting patients need to take for successful weight loss and/or maintenance.

5.1 Clarify Reasonable Goals

The health professional’s approach to setting goals and treating obese patients must be non-judgmental, respectful, and empathetic, allowing patients to feel comfortable with discussing their weight. The focus should be on an acceptable weight to achieve good health outcomes rather than simply reaching a lower body weight (35-37). Furthermore, the health professional must always keep in mind that overweight or obese patients are typically hesitant to broach the topic of weight loss, yet they likely wish for assistance in discussing, setting and achieving weight loss goals.

To demonstrate the importance of discussing weight loss with patients, one study showed that obese patients who had spoken with their health care professional about weight loss were three times more likely to lose weight than those who had not (38). Thus, it is important to talk with overweight patients about losing weight or, at the very least, about not gaining more weight. Patients typically do not like the terms “obesity,” “fatness,” or “excess fat.” Patients are more receptive to the terms “weight” and “excess weight.” It is wise to ask what weight-related terms are acceptable and offensive to them. Visit The National Institutes of Health’s Weight Control Information Network (WIN) at http://win.niddk.nih.gov/publications/talking.htmfor more information on discussing obesity with patients and for some examples of how to bring up the topic of weight loss with patients.

Determining whether a patient actually wishes to lose weight is pertinent and the first order of business. Patient involvement and investment are essential for weight loss success. If a patient is not ready to engage in weight loss, discuss the importance of weight maintenance and physical activity at visits until the patient is ready to begin weight loss therapy (2). Once the patient expresses the desire to lose weight, determine the patient’s weight-related goals and ascertain that goals are realistic and attainable. Agreeing on realistic goals facilitates maintenance of losses achieved (39). Unrealistic goals should be discussed and made into more achievable ones. Additionally, patients need to be reassured that the counselor is interested in their health as individuals, and that this concern will not change due to their weight loss or lack of it. The health care professional’s job is to reduce health risks and improve quality of life to the greatest extent possible within patients’ wishes (38).

Patients are often ready to abandon long term "healthy" measures (e.g., losing one-half to two pounds per week) in favor of more drastic measures if they feel that a risky weight loss strategy will work quickly. Healthy weight loss is key for long-term weight maintenance (39;40). Intensive very low-calorie diets (VLCDs; e.g., ≤800 calories per day) produce impressive weight loss results of up to 20% in the short-term, however greater than 50% of that weight loss is regained within one to five years (41). Patients need to understand that the primary reason for losing weight is health, and therefore weight control measures must be healthy. Concentrating on improving health and risk factors rather than simply on loss of weight is vital, since if this is the goal, health will inevitably improve. Once it is certain that the patient wishes to lose weight, the health professional should begin therapy by working with the patient to set a realistic, achievable, and sustainable weight loss goal (40). From the medical perspective, the weight goal is to maximize heath related effects while minimizing disruption to the patient’s quality of life from the reducing regimen. The physician is uniquely qualified to define and communicate what a "healthier" weight is to the patient since he/she has access to measurements of weight related risk factors that can be expected to decrease if weight is lost. Nurse practitioners, registered dietitians, physician assistants, and others should reinforce the message.

There is no single target weight. Weight reduction targets that are optimal vary depending on the patient’s weight and comorbidities. Progress toward healthier weight goals should involve a gradual approach that minimizes health risks and is timed to the patient’s level of readiness, motivations, and attainable short-term targets. Excess emphasis on the aesthetic and cosmetic aspects of weight loss should be avoided, as some patients have unrealistic fantasies of how much better they will look with weight loss (42). It is important to stress the health advantages of even modest weight loss (e.g., a half-pound per week). While some cosmetic improvement is possible with usual weight losses of five to ten pounds, the improvement is rarely as much as desired. The patient needs to be made aware of a realistic weight loss target through counseling. In time, greater weight loss may be possible if realistic goals are adopted, met, and sustained. The aesthetic and cosmetic effects of weight loss are "extra benefits." The primary medical concern is to help the patient lose enough weight to improve or maintain his/her health.

5.2 Adopt Realistic Goals that Include Health Objectives

The target is usually to achieve a weight loss of one-half to two pounds of body weight each week over six months (24 weeks), leading to a decrease of 5 to 10% in body weight from baseline. For example a 250 pound, 5’6’’ woman with a BMI of 40 losing 12.5 pounds over six months, would have a 5% weight loss, and an ending BMI of 38.5. A 10% weight loss would cause a fall in BMI to 36.3. The goal is maintence of the lower weight after a loss of 5 to 10% (38). The 5 to 10% is moderate enough to be achievable and may reduce fatness and weight enough to decrease some obesity-related risk factors, such as type 2 diabetes, hypertension, cardiovascular disease, and sleep apnea (7). The limit of about six months for dieting is because after about six months, most patients have great difficulty sustaining adherence, weight plateaus as energy intake fluctuates while resting metabolic rate and energy output decrease.

After six months of weight loss patients should focus on maintenance of the lost weight through a combination of diet therapy, physical activity, and behavior modification. If successful, after several months they can start a weight loss cycle again. When patients do not engage in a weight management program with all three components, the risk that they will regain all or some of the lost weight increases (40;43). Most individuals regain one-third of their lost weight in one year, and nearly half return to their original weight within five years (39). The more frequently a patient has contact with his/her health care provider, the more successful weight loss and maintenance outcomes tend to be (40).

5.3 Define Successful Outcomes for Weight Reduction with the Patient

Patient weight goals depend on their motivation, the salience of their weight to them, their perceptions of health risk, and other priorities in their lives. Some patients simply are not motivated to lose weight, or they are motivated but are not willing to do so at present. It makes no sense to give an unmotivated patient a weight loss goal that cannot be achieved. It is better to come to agreement about the steps that the patient is willing to take now to begin to deal with some other health problems. A technique used in counseling is “Motivational Interviewing” (MI); an egalitarian, empathetic approach to counseling. It uses specifics strategies, such as reflective listening, positive affirmation, and agenda setting to engage the patient in health behavior changes that will facilitate weight loss. MI’s goal is to assist individuals to work through their ambivalence about behavior change. Since patients often have strong aversions to the weight loss process, MI counselors reflect the patient’s doubts and provide opportunities for the patient to voice concerns about remaining overweight or gaining weight during counseling sessions. It may be more effective than the counselor simply stating facts to counter such beliefs. MI often enables patients to come to their reasons and plans for change. Individuals are more likely to accept and act upon opinions if they voice them themselves (22).

For patients who are already highly motivated or become so when they are told about the related health risks, the health professional’s job is much easier. However, these patients’ weight targets are often unrealistically low (e.g., targets of 25% or more of body weight) and their time frames for achieving losses are often unrealistically short (e.g., a few weeks rather than many months). Numerous studies have shown that obese individuals hope to lose 25 to 35% of their initial weight within a year or less of obesity treatment. In actuality, patients are likely to lose only 5 to 15% of their initial weight over a year of effort. Unfortunately, many dieters still often maintain unrealistic standards even when they are repeatedly informed that losing that much weight is not likely (44).

For example, Forrester and colleagues assessed the before-treatment weight loss goals of 45 obese women randomized to a behaviorally based weight-loss program over 48 weeks. While 8 to 10% of weight loss would have been a success from a medical perspective, the women identified a loss of 32% of their body weight as ideal. At the conclusion of their 48 week treatment, the women lost an average of 16% of their total body weight. Even though their weight loss was more than medically expected, the women collectively considered this loss to be “disappointing” (39). This study shows that most patients’ ideals for weight reduction are unrealistic and are often two to three times the 5 to 15% losses that motivated patients usually achieve (45). For them, advice and counseling on more realistic targets and time frames is helpful.

Because patient weight goals are often very different from those of their healthcare providers, health professionals must clarify patient expectations for treatment and the rationale behind these expectations and re-evaluate changes in expectations over the course of treatment (39). Providing patients verbal and written information on how much weight they can expect to lose with obesity treatment is helpful in damping unrealistic expectations and goals (44). Patients’ ideals of drastic weight loss, which are not met within their idealized time frame otherwise lead to disappointment and frustration so they must be addressed at the onset. It is also important to praise patients once they begin making health behavior changes. This helps them feel as though their efforts have been acknowledged and motivates them to maintain their new lower weight or to continue to lose more. Health professionals should also be sure to frequently reiterate the health benefits that a 5 to 10% loss of initial body weight will offer.

5.4 Define Dieting Success in Broader Terms than Weight Loss Alone

Definitions of success are always patient-specific, but health professionals should emphasize the importance of health goals rather than cosmetics as their definition of weight loss success. The definition of successful obesity treatment encompasses goals other than weight loss, and these broader health goals need to be communicated to patients. The reduction of risk factors, even if weight is not lost, is a "success" from the health standpoint. For some patients, prevention of further weight gain after years of slow, steady increase is “progress.” The maintenance of a reduced weight, even if it is still within the range of obesity as clinically defined is also a "success," since it reduces health risks. Some outcomes to focus upon in addition to a hypocaloric diet include improved metabolic profiles, such as lower blood pressure, serum cholesterol, or fasting blood glucose. The following health behavior changes also denote success: increased daily physical activity and fitness; greater consumption of fruits, vegetables and fiber; and reduction in dietary fat. Changes in specific unhealthful habits such as smoking, or overindulgence in alcoholic beverages, are also reasonable measures of success that may help enhance self esteem, self-efficacy, quality of life and functional capacity (2;4).

5.5 Set an Individualized "Healthier Weight" Target with the Patient

Patients are often unreasonably hard on themselves and believe that if they are to undertake weight reduction, drastic measures are necessary. A healthy weight goal consisting of an initial loss of 1-2 BMI units is often much less extreme than the measures patients think are necessary. For example, a 5’4’’ woman weighing 250 pounds with a BMI of 43 losing 5% of her body weight, or 12.5 pounds, will have an ending BMI of 41. This weight loss could take up to 25 weeks, if she loses a half a pound per week. A weight loss of a half a pound to two pounds per week is reasonable and offers the best chance for long term weight maintenance, but for very heavey people, this may mean many months or years before they reach their target. However, a loss of 10% body weight, if sustained, significantly reduces risks of coronary heart disease and other comorbidities (7;46). For this woman, a 10% weight loss would be 25 pounds, giving her a new BMI of 38.6. This weight loss would also probably improve her appearance. Perfection is unlikely, but some steps in a positive direction are possible.

Obese patients often expect to lose 25 to 35% of their initial weight over their first year of obesity treatment. Dieters often maintain these expectations even when they are repeatedly informed that they are likely to lose “only” 5 to 15% of their initial weight—even with pharmacological treatment, so the message needs to be repeated (44). The health professional must help patients adopt more realistic and achievable targets and help patients to achieve them. (44).

5.6 A Reasonable Target: 10% Loss of Body Weight over 6 Months

The 10% weight loss target can be achieved in most patients with a caloric deficit of 500 to 1,000 calories per day, leading to losses of a pound to two pounds a week. For women, a weight reduction plan of approximately 1,000 to 1,200 calories per day is suitable. According to the National Institutes of Health and the National Heart, Lung, and Blood Institute, a 1,200 to 1,600 calorie allowance for men or women who weigh 165 pounds or more or who exercise regularly is recommended. These levels along with increased physical activity and behavioral modification will usually produce a caloric deficit to achieve a one to two pound weight loss per week (47). With a caloric deficit of 500 to 1000 calories a day, after 6 months with perfect adherence, weight losses would theoretically be between 26 and 52 pounds. In actuality, losses are usually about 20 to 25 pounds, since adherence is never perfect (48).

A decrease of one BMI unit usually represents a loss of 10 to 15 pounds, but the exact amount depends on height and weight. A decrease in two BMI units over six months is another way of stating the weight loss goal. Reductions of this magnitude in weight usually decrease several risk factors such as blood glucose and blood pressure and thus alone should result in better overall health. Clothing should fit better and the patients’ appearance should be trimmer. If further weight reduction is necessary after 10% of body weight is lost, it can be attempted with a new reducing diet after the prior weight loss has been maintained for several months at a healthier level. Medical nutrition therapy for obesity should last at least six months or until weight loss goals are achieved, with a weight management program instituted after that, which entails all three components—diet, physical activity, and behavior therapy—to help prevent weight regain and maintain the patient’s new healthy lifestyle (40). Additionally, the patient should also have a strong social support network of encouraging friends and family as well as others who are undergoing weight loss treatment , to help the patient continue his/her healthier lifestyle (49).

5.7 Set an Increased Physical Activity Goal

If left to their own devices, without conscious awareness most dieters become more sedentary during weight loss, especially if diets are very low in calories. This is because a markedly negative energy balance reduces exercise tolerance and maximal power output and increases the sense of perceived exertion (50). Therefore, conscious efforts to increase physical activity while dieting require attention. However, physical activity alone only induces modest reductions in body weight. Few studies to date have used a large enough “dose” of physical activity to achieve even a 5% weight loss using a physical activity intervention alone. When physical activity is paired with energy restriction it has an additive effect on weight loss. Despite its modest effects on weight loss, physical activity is also essential for improving health-related outcomes relevant to many obesity related co-morbidities (e.g., heart disease, diabetes, cancer)(51). Physical activity is also vital in preventing weight regain and may enhance quality of life (52). There is a strong association between physical activity at follow-up and maintenance of weight loss. Data from the National Weight Control Registry,a registry of more than 3,000 individuals who have successfully maintained at least a 30 pound weight loss for a minimum of one year, shows that 90% of the individuals report that physical activity is crucial to their long term weight maintenance. They report expending, on average, 2,700 calories per week in exercise, the energy equivalent of walking four miles seven days a week (53).

5.8 Individualize the Diet and Treatment Program

Evidence-based reviews of successful weight control techniques increasingly emphasize the importance of individualized, multidisciplinary care, a health-outcomes focus, realistic goal setting and making permanent lifestyle changes, including an increase in physical activity (48;54).

The specific factors that induce a chronically positive energy balance differ among individuals. Daily lifestyle, environment, resources, and social situations may vary considerably. The weight reduction strategy must therefore be individualized in order to avoid positive energy balance, and to promote adherence and success (4). No single diet works for everyone. Different dietary approaches for maximizing adherence are successful to varying degrees in different individuals. If asked, patients can usually identify some strategies that have worked for them in the past and the health professional can build a program starting with this as a base. Previous pitfalls can also be identified and the new weight loss strategy can be tailored to avoid them. Candidates for weight reduction should discuss the approach that best suits their needs with their physician, dietitian, or other health professional. In addition to energy content, individual food selections, meal frequency and many other factors that can be tailored to make the diet better suit the individual from psychological, social, cultural, medical, and nutritional standpoints. Some factors to consider include the diet’s cost, convenience, how it approaches treatment of co-existing health conditions, and whether it assists patients to adopt strategies for healthful life-long weight maintenance (55;56).

Many overweight patients have already tried many times to lose weight on their own. For example, in the United States nearly half of women and more than a third of men report that they are attempting to lose weight at any given time (35). These self-directed efforts are usually motivated by aesthetic or social rather than health-related reasons. The goals they adopt are often unrealistically ambitious, the information they obtain on weight management is often inaccurate, and the motivation and support they receive is often inadequate from both health professionals and peers. Solo efforts often fail and lead to discouragement and a sense of futility (57). The vital role of the health professional is to provide the motivation, information, counseling, and support needed for patients to be more successful.

Throughout the weight loss management program, the patient must be counseled on sound eating patterns. Some dietary education topics that should be discussed to help patients are listed in Table 11. The National Institutes of Health (www.nutrition.gov), the American Dietetic Association (www.eatright.org) and other organizations, provide materials, checklists, guidelines, menus, and recipes to assist in such patient education (4;48). Resources for health professionals and for patients can also be accessed at websites such as MyPyramid.gov, the American Heart Association (http://www.americanheart.org/), American Diabetes Association (http://www.diabetes.org/), the American Cancer Society (http://www.cancer.org/), and the American Dietetic Association (http://www.eatright.org/).

Patients should maintain daily records of their food and beverage intake. Some may wish to also include their mood at the time of eating in order to help them recognize reasonsfor eating beyond hunger. Record keeping often increases awareness of consumption, and promotes dietary adherence. The patient should be encouraged to review the records each week and to identify an eating related behavior for the next week that can help him or her to focus effort.

6. Plan the Weight Reduction (Energy Deficit Phase) of Weight Control

This section will cover guidelines to follow during the energy deficit phase of weight reduction.

6.1 General Principles

For the individual who is already overweight, successful weight control first requires a hypocaloric phase in which dietary energy intake is reduced while energy output is increased (or at least not decreased). This phase is referred to as the "energy deficit" or "hypocaloric phase" of weight control. It is followed by a maintence phase.

The essential components of weight reduction, regardless of the type of diet, are decreased energy intake, increased energy output through physical activity, behavioral modification of lifestyles, and alterations in the larger environment that foster all of these measures and contribute to the energy deficit necessary to reduce weight. Although this chapter focuses on dietary measures in the treatment of obesity, all reasonable weight control programs should also include physical activity and behavioral modification.

6.2 Size of Caloric Deficit Needed to Lose Weight

Obesity results from the accumulation of excessive body fat as adipose tissue. An energy deficit of approximately 3,500 calories is required for an overweight person to lose one pound of fat. Although compensatory changes in resting metabolism, the energy cost of work, and discretionary physical activity may occur, which sometimes alter this figure by 100 to 200 calories, over the long-term, this relationship of 3,500 calories per pound of fat holds up quite well. Thus, it is the size of the energy deficit between actual energy needs and the energy output that determines the slope of decline in fatness over time.

As previously mentioned, a reduction of 500 to 1,000 calories per day is recommended to achieve a weight loss of approximately one to two pounds of body weight per week (i.e. -3,500 to -7,000 calories total). Cutting down on alcohol, dietary fats and/or carbohydrates is a practical way to produce this deficit (53).

6.3 Goal of the Energy Deficit Phase

The goal of the dietary treatment of obesity during the energy deficit phase is to decrease body fat stores without unduly depleting the lean body mass or otherwise compromising health. The lean body mass includes cells in skeletal muscle and the vital organs. During weight loss, some lean tissue is always lost along with the fat, but the goal is to keep this loss to a minimum(47). While weight is being lost, body stores of other nutrients such as water, vitamins, minerals and electrolytes must be maintained. Fortunately, dietary strategies are available to minimize loss of lean tissue and other nutrients. A systematic review of the scientific literature found that more lean tissue is lost if the energy deficit of the diet is too great and the rate of weight loss is too quick. In contrast, inclusion of exercise (both cardiovascular and resistance) and adequate dietary protein (a minimum of 60 grams per day, ranging from 0.8 grams to 1.5 grams per kilogram of body weight) helps to minimize lean tissue loss (56). These dietary strategies must be incorporated into sound dietary treatment plans.

7. Troubleshoot Diet Failures

Some of the many factors that contribute to patients losing less weight than they expect to while on reducing regimens, and what to do about it, are described below.

7.1 Remind Patients that Self-reports of Energy Intake are Almost Always Underestimated

The average healthy adult American male consumes approximately 2,800 calories per day, and the average female about 1,800 calories. Yet, such intakes are seldom actually reported when people recall or report their intakes. Instead, much less is reported. The reporting of energy intakes is difficult even for individuals who have been trained to report accurately. Simply put, people are unaware of what or how much they eat. Even small omissions or portion size and serving mistakes subtract hundreds of calories from usual intakes. Many days of observation are necessary since energy balance is only achieved over weeks, not days. Thus a report from any given day is certain to contain considerable random error if it is used to estimate usual calorie intake. Even more serious errors of a systematic nature (underreporting biases) are also present. Underreporting of energy intakes is common and large (20%) in virtually all people, and particularly so among the overweight (58). Objective biomarkers of energy output such as doubly labeled water indicate that underreports may be as great as 1,200 calories per day in very obese persons (59;60). Subjective reports of energy intake are often so low that if believed those who report them should be losing weight when in fact, they are gaining weight. It is biologically impossible to gain weight on a hypocaloric diet, and so underreporting must be considered (61).

The most common problem is that the patient’s weight loss is less, not more, than expected. This is largely a result of underreporting and underestimating intake. When overweight people report their intakes by recall, they often underestimate their intakes by 30 to 40%. They are likely to make similar mistakes in underestimating their intakes on reducing diets because of difficulties in portion size judgment, forgetting, the social desirability of reporting adherence to the prescribed regimen, and other factors. For example, many people underestimate or forget that their very large food intake on weekends “counts” or they forget to count in alcohol, snacks, or double portions of foods. Thus, on a 1,200 calorie diet, actual consumption may be 2,600 calories, or much more.

Methods for assisting dieters to decrease intake reporting errors include the use of household measures or weighing scales to determine amounts eaten more precisely, and the use of food diaries to help in self-monitoring of food intake. Portion-controlled liquid meal replacements, frozen low calorie entrees, and other foods that are fixed in their portion sizes may be helpful in controlling intakes at specific meals (see 10.3 Formulas and Meal Replacements).

Consistency in reporting does not necessarily mean that the report is accurate, especially among the very heavy. Underreporting is also especially pronounced among the severely obese, women, smokers, and those of low educational and socioeconomic status (59). Those who are underreporters tend to be consistent underreporters (59).

In spite of all these limitations, patients who keep food journals or diaries are more successful in losing and/or maintaining weight than those who do not (62). Additionally, self-reports are useful to the patient and counselor alike for obtaining clues on dietary patterns and portion sizes that may be helpful in counseling the patient and monitoring adherence. However, it is important to recognize their limitations.

7.2 Keep Food Records: Food Intake Varies from Day to Day and it is Easy to Forget to Diet Every Day

People vary in their eating patterns from day to day. Weight reduction prescriptions are sometimes given suggesting that the patient aim for a caloric deficit of approximately 500 calories per day to achieve a weight loss of about one pound per week. This is an abstract goal that is difficult to implement since the patient does not know how much he/she is eating in the first place. Since most people vary greatly in their food intake from day to day, they have great difficulty recognizing whether in fact they are eating less than previously. For this reason simply urging patients to "eat less" of certain foods in general is unlikely to help. More specific advice is more actionable. Examples of actions to decrease caloric intake include cutting down portion sizes of high calorie, frequently consumed foods; avoiding appetizers; eliminating a second cocktail; replacing a second serving of steak at dinner with vegetables; or ordering roasted, baked, grilled, or steamed foods instead of fried, deep fried, sautéed, or creamed items when dining out.

Patients should also be advised to increase foods that are low in caloric density in their eating patterns by increasing the fiber content of their foods and replacing fat with minimally-processed carbohydrates or protein. A diet rich in food that is low in energy density, such as fruits, vegetables, and soups, may reduce caloric intake while possibly promoting satiety. This strategy is thought to be superior to a fat- and portion-restricted diet for weight loss. Controlled laboratory studies have shown that the weight of food consumed is more constant than the calories eaten (63;64). When the energy density of food is decreased, but the volume of food remains the same, calories consumed will decrease. In one study, the energy density of foods was lowered by 30%, consequently, daily energy intake also decreased by 30% (64).

Providing a caloric recommendation and instruction to keep a food and physical activity record will help patients see the factors influencing their weight. Patients who record their daily food intake (i.e., food item, portion, calories, time of eating, and fat grams, if desired) as well as their physical activity for the day are more successful in their weight loss and weight maintenance efforts than those who do not (62). Some patients find it helpful to write down their emotions during their eating episode to help assess whether the patient partakes in emotional eating. The National Weight Control Registry data indicates that frequent self-monitoring of caloric intake and weight helps patients maintain their new lower weight (63).

Patients who self-monitor are more successful in their weight loss efforts than those who do not, since self-monitoring fosters awareness, an essential initial step in behavioral change. The Handbook of Assessment Methods for Eating Behaviors and Weight-Related Problems states that, “It is well established that self-monitoring or recording daily intakes via food records is a useful tool in weight loss programs” (65). Furthermore, the interplay among awareness, self-observation, recording, and self-evaluation can enhance self-management by improving how individuals attend to their health. A common denominator among all successful weight losers is self-monitoring (40;62;63;66). Patients who use food records report that they have a heighted awareness of their eating behaviors, they recognize the need to make significant dietary changes, they are more able to “stay on track,” and their label reading, fat and calorie counting, and portion determination skills are improved (66). These are all important skills overweight or obese individuals need in order to lose weight and/or maintain their weight at lower levels. They are also skills for making healthier lifestyle choices throughout their lives, thus improving their health.

7.3 Remind Patients to Stay Active: Self-reports of Energy Output Tend to be Overestimated

Self-reports of energy output as measured by physical activity questionnaires have been validated using doubly labeled water methods. Some lengthy questionnaires used for research purposes are quite good (67). However, the shorter questionnaires that are used clinically are not accurate for individuals (68). As is the case with dietary reports, physical activity questionnaires may be useful for self-monitoring, but should not be used for prescribing or assessing energy intakes or outputs precisely. Motion sensors (pedometers or accelerometers) have become popular in recent years. Accelerometers and pedometers provide objective physical activity measurements and are sensitive to walking (69). Either is a worthwhile purchase to help in self-monitoring of physical activity.

Accelerometers measure the body’s acceleration in one direction or more continuously for long periods. In contrast to the pedometer, an accelerometer distinguishes between different walking speeds and intensities. Many accelerometers also record step counts, allowing comparison with pedometers. Accelerometers have been validated as accurate in regards to steps counted (69). On the other hand, pedometers are cheaper because they measure only step count and not walking speed. Pedometers cannot distinguish between varying walking intensities. Furthermore, pedometers have a more difficult time in detecting steps if a person is walking slowly (e.g., less than two miles per hour). When a person is walking at this slow a pace, pedometers underestimate step count by approximately 50 to 90%. However, if a person is walking above 3.5 miles per hour, most pedometers approach 100% accuracy in step count (70). If a patient purchases a pedometer, piezoelectric type pedometers are best since they are more accurate than spring-levered pedometers, especially for obese or elderly individuals because they measure slow walking speeds more accurately (70;71).

If a motion sensor, be it a pedometer or accelerometer, has a calorie counter built in, it is likely to be inaccurate. Rather than focus on the inaccurate calories on the motion sensor, the patient should focus on the number of steps walked per day. Goals such as "10,000 steps a day" can be prescribed and patients can self-monitor their progress in reaching their goals. The ability for the patient to quantify physical activity in a demonstrable way fosters commitment, encourages performance, provides a realistic goal, and eventually may provide a feeling of self-accomplishment.

7.3.1 Compensatory Decreases in Energy Output Occur on Most Reducing Diets

Compensatory decreases in physical activity usually occur on reducing diets, particularly if diets are at a very restrictive energy level. These decreases result in slowed weight loss. As a rule of thumb, for every 500 calorie deficit, compensatory decreases in energy output due to decreased resting metabolic rate, discretionary physical activity, and the decreased energy cost of work involving moving the body are approximately 165 calories, leaving only 335 calories that actually contribute to weight loss. Thus, the caloric deficit again may prove to be less than anticipated and predicted weight loss therefore, becomes less than expected (72). Energy balance seems to be more strongly defended during energy deprivation than it is during energy surplus, impeding weight loss to a greater extent than weight gain (73-75). In part, this retarding effect on weight loss may be due to compensatory downward alterations in resting metabolism and in non-obligatory physical activity and thermogenesis that occur. By including physical activity during the weight reduction phase, these alterations can be ameliorated to some extent, in part through greater energy output and preservation of lean tissue (8), so this provides an additional incentive for patients to maintain physical activity.

7.3.2 Physical Activity Guidelines for Americans and Overweight Individuals

All weight loss programs should include physical activity. According to the 2008 Physical Activity Guidelines for Americans, recommendations for weight loss include engaging in 45 to 75 minutes of moderate-intensity activity per day, such as walking at three miles per hour, participating in water aerobics, ballroom dancing, or gardening. Alternatively, the individual may participate in 22 minutes of vigorous activity per day, such as swimming, jogging, jumping rope, or hiking. Once an individual loses weight, exercise still remains key for weight loss maintenance. For weight maintenance, 60 minutes of moderate activity per day or 30 minutes of vigorous activity per day is recommended. In addition, muscle-strengthening activities, which involve all major muscle groups, should be performed on two or more days per week. If these recommendations cannot be achieved, the patient should be reminded that some activity is better than none and he should use the aforementioned parameters as goals. Energy intake must always be considered in any discussion of weight control (76).

7.4 Remind Patients that Shifts in Water Balance May Obscure True Decreases in Body Fat and Overestimate Fat-related Weight Loss

Dramatic alterations in weight often occur on reducing diets, particularly in the first few weeks, especially on severely hypocaloric regimes (with deficits of 1,000 calories per day), and on ketogenic diets (77;78). These fluid shifts depend on the caloric level and macronutrient composition of each diet. For example, high protein, low carbohydrate diets increase obligatory urine volume due to greater urinary loads of nitrogen or other solutes and will result in increased fluid losses from the body. Excess loss of lean tissue is also associated with large body water losses because tissues, such as muscle, are approximately 73% water. Fluid losses are also more apparent on hypocaloric regimes that are very low in carbohydrate (<100 grams/day and especially <50 grams of carbohydrate). Shifts in water balance may cause very dramatic deviations from the usual linear slope of weight loss. They may also result in very rapid weight accumulation over a few days during periods of non-adherence resulting from storage of glycogen and water with carbohydrate refeeding after a period of carbohydrate deprivation. This is because for every one gram of glycogen stored, three grams of water are associated with it. Thus, gains or losses of glycogen are associated with changes in body water balance and water weight. These shifts can be sudden and alarming to the dieter.

7.4.1 Weight Loss Varies with Water Balance Shifts

Water balance and weight often will shift during the initial period of a weight reduction program, particularly on a very low carbohydrate diet. As glycogen stores are depleted in response to reduced carbohydrate intake, the resultant diuresis produces an initial and often dramatic weight loss. However, the steep rate of initial weight loss will not continue. Patients should be reminded that one-half to a pound per week of fat loss is a realistic plus achievable goal that will improve their health. Additionally, it is difficult to continue losing weight as rapidly as at the start of a low carbohydrate reducing diet since glycogen stores are being depleted; hence, there is less water weight to lose. A recent position paper on Weight Management concluded that, “On very-low-carbohydrate diets (e.g., <20 grams per day) the body produces ketones to sustain fuel utilization in the brain, which may in turn help with diet adherence by decreasing hunger. Individuals assigned to ad libitum low-carbohydrate diets in recent randomized controlled trials lost more weight at six months than individuals assigned to low-fat, reduced-energy diets, but this difference was no longer significant at 12 months” (53).

7.4.2 Remind Patients that Fat Loss and Weight Loss Do Not Always Track over the Short Run, Although They Do Over the Long Run

Over the long run, fat loss and weight loss closely parallel each other. However, this is not necessarily true over the short run. The amount of weight that is lost over time, particularly over the short run of several days depends not only on the energy deficit from current needs, but on adherence to the weight reduction plan, and on shifts in water balance, which may be considerable over the short run. These shifts may accentuate the fat loss that is actually occurring. Such considerations, which are often unrecognized by patients, make many skeptical about whether such predictions actually apply to them.

8. Set the Caloric Level of the Reducing Diet

From the clinical standpoint, hypocaloric diets must be defined in terms of the energy needs of the individual, since it is the size of the energy deficit that will determine the physiological effects expected. “Estimated energy needs should be based on resting metabolic rate (RMR). If possible, RMR should be measured (e.g., with indirect calorimetry).” Products such as the MedGem^TMindirect calorimeter can be used in an office environment to quickly, easily, and accurately determine a patient’s RMR (79). However, “if RMR cannot be measured, then the Mifflin-St. Jeor equation using actual weight is the most accurate for estimating RMR for overweight and obese individuals” (40;53). According to the American Dietetic Association’s Evidence Analysis Library (EAL), “one study of high research quality design reported that the Mifflin-St. Jeor equation accurately predicted RMR using actual body weight within +/- 10% of measured RMR in 70% of obese individuals. Of the remaining 30%, 9% were overestimations and 21% were underestimations. The individual error range was a maximum overestimate of 15% to a maximum underestimate of 20%” (2). To date, the Mifflin-St. Jeor equation is most accurate in predicting RMRs of overweight and obese patients. It is the recommended equation to use for these patients (40).

After calculating the patient’s RMR, his/her RMR should be multiplied by an appropriate physical activity factor to provide a baseline caloric level for weight maintenance. Once a baseline caloric level is configured, the patient’s caloric level should be reduced to facilitate weight loss. Reducing the calorie level by 500 calories is a common strategy to yield a weight loss of approximately one pound per week. However, depending on the patient’s BMI and current intake, a larger reduction in calories may be needed. Calculations for estimating energy needs and various physical activity factors are provided in Table 12.

The major determinant of weight loss on reducing diets is size of the actual, and not the prescribed, caloric deficit. All diets that reduce caloric intake to about 1,400 to 1,500 calories in most American adults (lower in females) will result in weight loss if they are adhered to perfectly, regardless of their macronutrient composition (80). Therefore, the caloric level of the diet requires attention first and foremost; after this, other characteristics of the diet can be considered. Diets that reduce caloric intake relative to energy expenditure result in weight loss. The optimal diet for weight loss of sedentary people in the absence of alterations in physical activity is one that provides roughly 1,000 to 1,600 calories per day, depending on sex, weight, and physical activity level, regardless of its macronutrient composition.

8.1 Low-Calorie Diets (LCDs): 1,000 to 1,200 Calories for Females, 1,200 to 1,600 Calories for Males

Low calorie diets of 1,000 to 1200 calories for women, and 1,200 to 1,600 calories per day for men, are currently recommended by the National Institutes of Health for weight loss in most individuals (2;48). The rationale is that on such regimens, a deficit of approximately 500 to 1,000 calories per day will be created, which should result in a slow progressive weight loss of one to two pounds per week. The dietary composition of the recommended reducing diet is similar in macronutrients to that of the National Heart, Lung and Blood Institutes (NHLBI) Step 1 diet to decrease risks of high blood cholesterol and blood pressure (2). Two sample menus and other materials at 1,200 and 1,600 calories and many aids to assist the physician are provided in the NIH monograph (48). The MyPyramid.govwebsite also provides such materials that can be accessed by consumers.

It is important to recognize that when using fixed 1,200 to 1,600 calorie reducing diet plans such as those provided in NIH recommendations that even with perfect adherence, individuals will vary greatly in their weight loss. This is because their resting energy needs and physical activity, and thus energy outputs, often differ markedly.

The National Institute of Health’s Obesity Initiative sponsored an evidence based review of low calorie diets (48). It found that on average, diets such as these reduced body weight by an average of 8% over three to 12 months of treatment, and that the losses were accompanied by decreases in abdominal fat, which is the type of adipose tissue deposition that is associated with highest chronic disease risk. However, no improvements were noted in cardio-respiratory fitness as measured by VO2 max unless the dieters also increased their physical activity (2).

There are many pre-packaged meals on the market that fit into the low-calorie diet category, including Weight Watchers®^TMmeals, Jenny Craig®^TM, and NutriSystem^TM. See Table 20for a list of these products.

8.2 Very-Low-Calorie Diets (VLCDs): ≤ 800 Calories

VLCDs supply fewer than 800 calories, a total of 50 to 80 grams of protein, 100% of the Reference Daily Intake (RDI) for vitamins and minerals per day, and are designed to produce very rapid weight loss while still preserving lean body mass (28). VLCDs are prescribed as a form of intensive diet therapy, in order to induce quick and significant weight loss (13 to 23 kilograms) over a short time (three to six months). This is typically done through meal-replacement liquid diets (5). Any diet, regardless of its caloric level, that provides less than half of an individual’s energy needs can be considered a VLCD for that individual. However, virtually all adults have energy needs that exceed 1,000 calories per day, and therefore any diet below 500 calories, and for most individuals, diets below 800 calories, are VLCDs. Depending on a person’s caloric requirements, other regimens that are higher in calories may also be VLCD for some people with very high energy needs using this same rule of thumb; for example, a 1,200 calorie diet prescribed to a man whose usual intake is 3,000 calories would also qualify as a VLCD.

8.2.1 Uses and Candidates for Therapy

These VLCDs are reserved for special uses and for individuals at high risk because of their potential for greater adverse metabolic effects and the consequent need for more extensive medical monitoring. VLCDs are often used when the health risks from obesity are particularly acute and threatening so that it is imperative to lose weight. Other individuals can usually reduce just as well on a LCD with less risk and discomfort (81).

According to the National Task Force on the Prevention and Treatment of Obesity, VLCDs in patients with BMIs >30 are usually effective in promoting significant short-term weight loss, in addition to improving coexisting obesity-related conditions (e.g., obstructive sleep apnea, poorly-controlled type 2 diabetes, hypertriglyceridemia) (82). However, these diets require close metabolic monitoring, and should only be prescribed and adjusted under the supervision of a physician specializing in obesity care. Medical contraindications include recent myocardial infarction, cardiac conduction disorders, history of cardiovascular disease, renal or hepatic disease, cancer, type 1 diabetes, and pregnancy. Behavioral contraindications to their use include bulimia nervosa, major depression, bipolar disorder, substance abuse, and acute psychiatric illness. The advantages of the VLCD for patients include a rapid improvement in blood pressure, blood glucose, serum lipids and often-psychological status. For those who require surgery, the rapid loss of weight may reduce surgical risks.

8.2.2 Formulations Available

The hallmarks of the VLCD are the low calorie level and a relatively high percent of protein; 0.8 grams to 1.5 grams per kilogram of ideal body weight (28;83). Protein needs are elevated on VLCD because in the hypocaloric state, the efficiency of protein utilization for maintaining the body’s lean cell mass is lessened. Also, very heavy people who often are candidates for therapy have a larger lean body mass, and thus more lean tissue, as well as much more fat than their smaller peers. Even after adjustment for their greater fatness, total protein needs, which are most highly associated with the size of the lean body mass, are elevated. Therefore, higher protein levels may help to preserve protein nutritional status. VLCDs also have extremely low fat content and relatively low carbohydrate levels, making them ketogenic. Without special formulation or supplementation, the VLCD is deficient in several vitamins and minerals, specifically potassium, calcium, iron, zinc, vitamin C, vitamin B6, copper, and possibly other nutrients.

There are two major types of VLCDs currently in use; commercial and "home-made" preparations. The commercial preparations include powdered products that are rich in egg- or milk-based proteins, are mixed with water, and consumed four to five times per day. The commercial products must provide at least 70 grams of protein by law, and often contain much higher amounts of high quality protein (70 to 100 grams), 50 to 100 grams carbohydrate, and up to 15 grams fat per day, plus vitamins and minerals in amounts to meet the Recommended Dietary Allowances (RDA). These products are formulated under FDA regulatory specifications. They are convenient and have a predictable and adequate composition when used as directed. Their major disadvantage compared to home preparations is their higher cost. The formulas or prepackaged meals are relatively choice-free and help dieters avoid contact with conventional foods, which in some cases may facilitate dietary adherence and remove temptation.

Several commercial weight loss programs are available that provide an entire program of VLCDs plus the other essential aspects of a sound weight control program, including dietetic advice, exercise, behavioral modification, and supervision during the VLCD and post VLCD phases. The choices include the programs of HMR^TM(Health Management Resources), Optifast^TM(Novartis Nutrition), and Medifast^TM. These programs employ health professionals who are trained in weight management, and a structured program that encourages adherence. The major disadvantage is that they are expensive ($3,000 to $34,000 for 26 to 28 weeks), and costs may not be covered by health insurance (83). Also, there is the uncertainty that the weight which is lost will remain so over the long run. Therefore a serious investment of effort in long-term weight management is also mandatory. See Table 13for available program details.

The "home made" VLCD regimens are sometimes referred to as "protein-sparing fasts", or "protein sparing modified fasts" (PSMF). This is a misnomer since they do not “spare” protein except in contrast to a total fast. They are usually based on lean meat, fish or poultry and a few other foods plus supplements of two to three grams of potassium chloride and a multivitamin/multimineral supplement in amounts approximating the Recommended Dietary Allowances (RDA). Without such supplementation, they may be nutritionally inadequate. When patients are provided with appropriate dietetic counseling and health supervision by a physician who is experienced in the use of VLCDs and other aspects of a complete weight reduction program, these formulations are also safe and generate rapid weight loss. The extremely hypocaloric versions of VLCDs (e.g., less than or equal to 800 calories per day), which are low in carbohydrate and sodium, promote a mild ketosis that gradually leads to diuresis and rapid weight loss in the first several days on the diet.

8.2.3 Use of Very-Low-Calorie Diets (VLCDs)

Evaluation of general health and cardiac status is important prior to the institution of a VLCD. Evaluation of medication dosages and physician monitoring during the regimen are also important, since with weight loss dosing may need to be adjusted. Many practitioners begin the regimen with a two to four week LCD phase to assess the ability to comply with a restrictive regimen, and to begin the weight loss process. This is followed by a 12 to 16 week VLCD phase; the regimen is limited to this amount of time to avoid excessive loss of lean tissue. The VLCD phase is then followed by a 12 to 14 week refeeding phase of transitioning back to usual foods and gradually increasing caloric levels. The goal is to increase calories from healthful foods up to 1,200 to 1,500 calories per day, increasing caloric intake by 100 to 150 calories per day (28). This helps to avoid rapid weight changes due to refeeding with restoration of glycogen stores and shifts in water balance. The refeeding phase also provides a time for assisting the dieter to plan a maintenance diet on conventional foods and to solidify a physical activity schedule. VLCD are most effective when administered as part of a more general weight control program that includes physical activity, nutrition education, behavioral modification and attention to decreasing other risk factors. If additional weight loss is needed, it is recommended that several months elapse before another VLCD phase is instituted (84). Although lean tissue is lost on most weight reduction diets, this is a particular risk on VLCD, since greater energy restrictions are associated with more lean tissue losses (56).

8.2.4 Safety of Very-Low-Calorie Diets (VLCDs)

The VLCD induces semi-starvation, which has both benefits and risks to the patient. Occasionally, with inadequate commercial products, such as one sold in the 1970’s that consisted of hydrolyzed collagen (an incomplete protein) with inadequate amounts of electrolytes, vitamins and minerals, deaths occurred (85). Today, commercial products are better regulated and are nutritionally complete by law, however, the potential for misuse still exists.

Some physiological effects are inevitable on VLCDs. On VLCDs mild ketosis occurs and increases risks of dehydration, although dehydration can be avoided by ample fluid intake. Patients on VLCDs should drink at least two liters of non-caloric liquids per day (preferably water) to make up for decreased food intake and to prevent dehydration. Avoidance of caffeinated beverages is recommended, as they can further the risk of dehydration (28). Electrolyte imbalances may occur, and so may nutrient deficiencies if measures are not taken to prevent them on "home-made" VLCD by use of appropriate supplements. Minor side effects that occur, even with appropriate physician monitoring of cardiac and general health status, include fatigue, dizziness (due to orthostatic hypotension), muscle cramps, gastrointestinal distress (constipation and/or diarrhea), and cold intolerance. The risk of cholelithiasis (gallstones) is increased, and seems to be particularly high when weight loss is very rapid (e.g., >1.5 kilograms/week). The risk of cholelithiasis can be decreased by administering ursodeoxycholic acid, including a moderate amount of fat in the diet, and limiting the amount of weight loss to 1.5 kilograms per week (83).

8.2.5 Effectiveness of Very-Low-Calorie Diets (VLCDs)

Because these VLCDs are so low in energy, they usually produce a greater initial weight loss than LCDs. Patients who completed a comprehensive VLCD program including lifestyle modification lost an average of 15 to 25% of initial weight within three to four months (83). However, in comparisons of VLCDs with energy levels of approximately 800 calories versus diets at lower caloric levels of 400 to 500 calories, the lower VLCDs did not necessarily result in greater weight loss, perhaps because compensatory reductions in resting energy expenditure, discretionary physical activity, and the lack of adherence on the lower calorie regimes thwarted weight loss (86).

There seems to be little difference in outcomes between commercial and properly formulated homemade VLCDs. The NIH expert panel review of existing studies found that preservation of weight loss over the long-term (e.g., >1 year) was not different on VLCD from that of LCD since most patients gained back 30 to 50% of the lost weight. Studies of VLCDs vary in their long-term results, but weight regain is common. Combining a VLCD with behavior therapy, physical activity, and active physician follow-up may help to prevent this weight regain, and lend to greater weight loss (87). As such, the long-term advantages of VLCDs in weight control are unclear. Although weight gain is common after cessation of VLCDs, individual clinicians may decide that the expense and quick initial weight loss are worth it for the patient (28).

8.3 Fasting and Alternate Day Fasting

Total fasting is contraindicated for weight reduction because it causes excessive breakdown of lean tissue and ketosis. Also, the compensatory decreases in resting metabolism and physical activity on total fasts are profound and counterproductive, since they lower energy output (2;4).

Short-term modified alternate-day fasting (ADF) is a new dietary strategy that has not yet received enough research attention to support the effectiveness of its use. In an ADF diet, a patient is to consume 25% of their energy needs on the fast day, and food intake ad libitum the next day. Varady et al found that ADF was a viable diet option, helping obese patients not only to lose weight, but to also decrease their risk of coronary artery disease (CAD) (88). Further research is needed before its widespread use for weight loss purposes, however.

9. Consider the Composition of the Reducing Diet

The composition of the reducing diet influences the composition of the weight that is lost and nutritional status, and therefore is also important. An overview of some popular diets and the basic principles that must be considered in weight control can provide more information (55;72;80;89).

Dietary composition on reducing diets should be geared towards decreasing risks of nutrient inadequacy and diet-related chronic diseases. Accordingly, the diet should be adequate in nutrients, with ample intake of vitamins and minerals; relatively low in fat, saturated fat, cholesterol, and sodium; and high in both soluble and insoluble fiber (2). Consumption of fruits, vegetables, legumes, whole grains, lean sources of protein, and water should be encouraged, with emphasis on balance and moderation(24). Diets that promote extreme restriction or unusually high intakes of any macronutrient or food should be limited to a short amount of time. Recommendations for healthful composition of weight reducing diets are outlined in the 2005 Dietary Guidelines for Americans (Table 1) and discussed further in this section.

9.1 Macronutrient Distribution

The macronutrient composition of the diet does not appear to play a major role in overall weight loss; reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize (90). There is one exception: over the short term, low carbohydrate diets are ketogenic, and may cause a greater loss of body water than body fat (at least in the first few days of the diet). Water weight is regained when the diet ceases, or when carbohydrate intake increases. Generally, when any reducing diet is maintained over the long term, if it remains hypocaloric, it will result in a loss of body fat – regardless of the distribution of macronutrients.

Although weight loss is caused by many reduced-calorie diets, the nutritional adequacy of different calorie levels and macronutrient composition for weight loss diets varies (91). The lower the reducing diet is in calories, and the more its composition differs from usual levels, the greater the risk of nutrient inadequacy. For the most part, moderate fat, balanced macronutrient reduction diets are nutritionally adequate. Very low-fat diets tend to be deficient in vitamins E, B12, calcium, iron and zinc. High fat, low carbohydrate diets are nutritionally inadequate, and require supplementation to make them nutritionally adequate in many nutrients (78;92;93). Dietary supplements used on weight reduction diets should be within RDA levels and below upper safe limits.

Metabolic parameters may improve on some various popular diets including decreased blood pressure, blood lipids, blood sugar, and serum insulin, related to energy restriction and weight loss, regardless of the macronutrient composition of the diet. However, there are some differences. Moderate fat, balanced nutrient reduction diets lower low-density lipoprotein (LDL) cholesterol, normalize plasma triglycerides, and normalize ratios of HDL/total cholesterol. High fat, very low carbohydrate diets result in ketosis. Low and very low-fat diets (e.g., 15-20% of calories) reduce low-density lipoprotein (LDL) cholesterol, and after a transient rise in triglycerides, may also decrease plasma triglyceride levels. Low carbohydrate diets (e.g., <100 grams of carbohydrate) that result in weight loss may also cause a decrease in blood lipids, blood glucose and insulin levels, and blood pressure. However, these diets are often high in saturated fat, total fat, and in dietary cholesterol, and low in plant-based nutrients such as fiber. Moreover, they are ketogenic, often causing signs and symptoms such as dizziness, halitosis, fatigue, weakness, hypotension, and malaise.

Hunger may vary on the different diets, and also from one individual to the next, but little objective evidence is available for comparing different reducing diets on their anti-hunger effects. Many factors affect hunger, appetite and subsequent food intake, including interactions between physiological and non-physiological factors. Schoeller and Buchholz speculate that a greater consumption of protein may increase satiety, which in turn results in better adherence to hypocaloric diets, however, substantial evidence to support this supposition is lacking (93), and more research is needed in this area.

Long-term dietary compliance is likely to be a function primarily of psychological issues rather than macronutrient composition itself. At present little is known about the nutritional or other characteristics of diets that maximize adherence. It is likely that "one size does not fit all" in this respect, so the importance of individualization is underscored.

9.2 Protein

This section outlines dietary protein needs during weight reduction. The Recommended Dietary Allowance for protein is 0.8 grams per kilogram per day, but most Americans eat about 1.2 grams per kilogram per day, or approximately 15% of their total caloric intakes from protein. For people in energy balance and at a stable weight, the World Health Organization (WHO) recommends that dietary protein should account for approximately 10 to 15% of energy intake (94).

9.2.1 Protein Needs During Weight Reduction

Protein requirements do not decline, and may actually rise, on hypocaloric diets, especially on VLCDs when protein is burned for energy and this needs increase is necessary for energy balance if lean body mass is to be maintained. This is because when energy intakes are insufficient, glucogenic amino acids are used to maintain blood glucose levels and other ketogenic amino acids must be used for energy, so overall protein requirements increase. Fortunately, the hormonal milieu in hypocaloric states spares nitrogen to some extent and causes preferential use of fat for energy. However, fatty acids cannot be converted to blood glucose, so glucogenic amino acids are needed for this. Inevitably, as adipose tissue is mobilized some lean tissue is lost and consequently some nitrogen is also lost. Losses of water, calcium, phosphorus, potassium, and vitamins follow the loss of lean tissue. Excess losses of lean body mass can be hazardous, affecting cardiovascular function, exercise tolerance, and possibly immune responses, and thus should be avoided. As mentioned previously, excess loss of lean tissue can result from energy deficits that are too great (56).

As a rule of thumb, a minimum of 65 to 70 grams of protein is needed daily. On a VLCD, 1.5 grams of high quality protein per kilogram of ideal body weight per day is desirable, with intakes no less than, and preferably more than, 65 to 70 grams daily. Intakes may need to be even higher if the dieter suffers from certain diseases or is physically stressed, since nitrogen losses may be more extreme in these states. On diets providing 600 to 1,200 calories per day, daily protein intake should be at least one gram per kilogram ideal body weight per day. Reducing diets over 1,200 calories per day should supply at least 0.8 grams per kilogram ideal body weight. Levels should remain this high after weight loss has stopped and maintenance has begun.

9.2.2 High Protein Weight Loss Diets

High protein reducing diets are those that provide more than 1.6 grams per kilogram of desirable weight per day. Self-prescribed high protein reducing diets vary in their composition from about 28 to 65% of energy, providing 71 to 163 grams of protein per day. They are currently popular as a new strategy for losing weight, and are usually quite low in their carbohydrate content. Some are clearly ketogenic, and severely limit carbohydrates to below 50 grams per day. Examples include the Doctor’s Quick Weight Loss Diet(95)and Dr. Atkins™’ Diet Revolution(96).

Other diets are extremely high in protein, very low in carbohydrate and ketogenic, but also very high in fat, such as Protein Power(97). Two other high protein diets with enough carbohydrate so that they are not likely to be ketogenic are The Zone(98)and Sugar Busters(99).

Many high protein diets include elaborate instructions that prescribe strict, structured eating schedules, and involve limited food variety and dietary flexibility. The high protein diets that are ketogenic also induce quick initial weight loss because of their low caloric level, and their diuretic effect owing to glycogen depletion, and sodium and water loss. They may also be associated with decreased appetite due to the high protein intake, since protein may show to be particularly satiating (100;101). Ketosis has long been said to reduce appetite, although little data supports this. Nonetheless, for some patients these constraints may help them to achieve and maintain low calorie intakes over the short run.

Popular high protein reducing regimens are not risk-free, however. Many of these diets advocate very high intakes of protein from meat and other foods that are also often high in saturated fat, cholesterol and sodium while they are low in dietary fiber, antioxidants, potassium, calcium, magnesium, and some vitamins. This can potentially increase one’s risk for cardiovascular disease. The purine content of meat, poultry, seafood, eggs, seeds, and nuts is high, and can increases uric acid levels and risk of gout in susceptible persons. The high protein load may also increase urinary calcium loss if it is not buffered (102). In patients with diabetic nephropathy, very high protein diets may speed progression, although the data are not definitive (103). Because many high protein diets are often by default low in carbohydrate, they also can cause an increase in ketosis. Finally, and perhaps most important, there is no objective evidence to indicate that these diets promote greater weight loss, or that the weight loss is better sustained for a longer period of time. For these and other reasons, the American Heart Association does not recommend high protein diets, and cautions that if they are used at all, they be limited for a short period of time (104;105).

9.3 Fat

This section outlines dietary fat needs during weight reduction.

9.3.1 Fat Needs During Weight Reduction

Even on reducing diets, the human body needs small amounts (e.g., three to six grams) of essential fatty acids (linoleic or arachidonic acid). Some fat is also necessary as a carrier for the fat-soluble vitamins A, D, E, and K. Therefore the diet should not be devoid of fat. However, because fat is calorically dense, it is usually decreased on reducing diets to reduce energy intake while increasing bulk.

9.3.2 Moderate to Low-Fat Balanced Deficit Reducing Diets

In general, levels of dietary fat, saturated fat, trans fat, polyunsaturated fat, monounsaturated fat, and cholesterol should follow guidelines from the American Heart Association (AHA) on weight reduction diets. While lower levels may be appropriate in some cases, they amply meet requirements while supporting cardiovascular health (2).

Weight reduction diets that are moderate to low in fat (20 to 30% of calories) are called "balanced deficit" diets because they maintain a reasonable balance among macronutrients similar to that recommended in MyPyramid.gov, DASH, and the Dietary Guidelines for Americans(13). They tend to achieve most of the caloric deficit by reducing fat from the typical level in North American Diets of about 34% or more of calories to 20 to 30% fat, 15% protein, and 55 to 65% of calories from carbohydrates. Some examples of balanced deficit diets are the Weight Watchers® Diet (25% fat, 20% protein, and 55% carbohydrate, with 26 grams of dietary fiber), Jenny Craig®, the National Cholesterol Education Program Step 1 diet (25% fat), diets based on the Food Pyramid, the DASH diet, the Shape up and Drop 10 diet of Shape Up! America (24), and the Nutrisystem® diet. These dietary patterns have been extensively reviewed and appear to be optimal for weight reduction on low calorie diets for most individuals.

9.3.3 Very Low-Fat Reducing Diets (<20% Fat Calories)

Very low-fat diets such as the Pritikin Diet (106)and the Ornish Diet (107)are advocated not only for weight reduction, but also for improving cardiovascular risk profiles. The Ornish Diet, which is very low in fat (13% of calories) and saturated fat, very high in carbohydrate (81% of calories) and very high in fiber (38 grams), is part of a program that includes nonsmoking, exercise and behavior modification. It was shown to reduce some cardiovascular risk factors in a limited long term study (107). For those who can adhere to the Ornish regime it may be helpful.

9.3.4 High Fat Diets for Weight Reduction (55 to 65% Fat)

High fat reducing diets are also usually low or very low in carbohydrate (<200 grams carbohydrate per day). Some current examples include Dr. Atkins™’ Diet Revolution (96), Protein Power(97), the Carbohydrate Addicts Diet (108), Dr. Bernstein’s Diabetes Solution (109), Life Without Bread (110), and the Pennington Diet (111). There is some evidence that free-living, overweight people who self-select high fat, low carbohydrate diets consume fewer calories and lose weight (80). This is not because the laws of thermodynamics are violated, but because there is so little for them to eat, if they adhere to such rigorous regimens. When high fat, low carbohydrate reducing diets are fed they also tend to cause ketosis and diuresis. They may also result in decreased blood lipids, decreased blood glucose and insulin and decreased blood pressure, but only if weight is lost. Over the short term (a few days or a week) high fat, low carbohydrate, ketogenic diets cause a greater loss of body water than body fat, but water balance is quickly restored when carbohydrate levels increase or when the diet ends. High fat, low carbohydrate diets are often nutritionally inadequate and require some supplementation with micronutrients. If such high fat levels are continued on a chronic basis after weight is lost, they are likely to increase dietary risks for coronary artery disease.

9.4 Carbohydrates the Glycemic Index

The following section reviews carbohydrate needs during weight reduction, and the glycemic index.

9.4.1 Carbohydrate Needs in Weight Reduction

Carbohydrate needs for an individual are at least 50 grams per day. At least 100 grams carbohydrate, and preferably carbohydrate within the Acceptable Macronutrient Distribution Ranges (AMDR) of 45 to 65% of total energy intake, should be provided for diets that are over 800 calories per day. Under experimental conditions, both hypocaloric diets very high in sugars (mono-and di-saccharides) and diets very high in starches (digestible polysaccharides) that are equicaloric have similar weight loss effects (112;113). However, from the practical standpoint, since many products that are high in sugar are calorically dense and often are also high in calories, added fat, and low in fiber, vitamins and minerals; sugars are usually limited on reducing diets.

Numerous studies have been conducted on carbohydrates’ role in weight loss. A recent study concluded that a reduced calorie diet results in clinically meaningful weight loss regardless of what macronutrients are emphasized. In this study, 811 overweight adults were placed on one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. After six months individuals lost an average of six kilograms, 7% of their initial body weight, and after 12 months they started to regain weight. At the end of the two-year study there were no differences in the amount of weight lost amongst participants. Changes from baseline differed among the different diet groups by less than 0.5 kilograms of body weight, and less than 0.5 centimeters at the waist. However, all of the diets reduced risk factors for cardiovascular disease and diabetes at both six months and two years (114).

Individuals assigned to a low-carbohydrate, high-protein diet do lose more weight at six months than those on low-fat, reduced-energy diet. However, this difference is no longer significant at 12 months (53;89;114). A recent evidence review concluded that, “An individualized, reduced calorie diet is the basis of the dietary component of a comprehensive weight management program. Reducing dietary fat and/or carbohydrates is a practical way to create a caloric deficit of 500 to 1,000 kcal below estimated energy needs and should result in a weight loss of one to two pounds per week” (53). Whether an individual dieter reduces fat or carbohydrate does not matter. If calories are similar, in the long run, weight loss amounts to reducing caloric intake. Concerns regarding an increase in cardiovascular risks with low-carbohydrate diets now do not appear to be as problematic as first thought (53).

9.4.2 Low Carbohydrate Diets (<100 grams Carbohydrate)

Diets providing less than 100 grams of carbohydrate per day, and especially those with less than 50 grams carbohydrates per day, are ketogenic. Ketosis can be a problem on some popular diets that are very low in carbohydrates, such as Dr. Atkins™’ Diet Revolution (96), Protein Power (97), the Carbohydrate Addicts Diet (108), Dr. Bernstein’s Diabetes Solution (109), Life Without Bread (110), and the Pennington Diet (111). Also, VLCDs containing fewer than 100 grams of carbohydrate per day are ketogenic and may lead to excessive protein breakdown to maintain blood glucose levels unless protein intakes are increased. When the body must rely on degradation of protein to preserve blood glucose levels via gluconeogenesis, the catabolism of the protein is accompanied by loss of water. For every gram of protein (or glycogen) that is broken down, three grams of water are released, causing rapid weight loss but also a state of relative dehydration (77). Relative dehydration caused by ketosis and failure to drink adequate amounts of fluids is not only undesirable for health reasons, it reduces exercise tolerance (50). It also does not address the primary purpose of the weight-reducing strategy, which is to decrease excess adipose tissue and not water weight.

9.4.3 Low Glycemic Index Diets

The Glycemic Index (GI) was originally developed for the therapy of diabetes, but it has recently become popular in weight management. The GI describes the blood glucose response resulting from consumption of a defined amount of carbohydrate (usually 50 grams) from a given food, relative to the response of the same amount of carbohydrate from a control food (usually white bread)(115). In brief, the GI is an alternative system for classifying carbohydrate-containing foods according to their postprandial blood glucose responses to portions containing standardized amounts of carbohydrates (22). Since the GI is based on standardized portions, glycemic load (GL), the product of GI and carbohydrate amount, is used to evaluate the affect of meals/snacks—differing in both quality and quantity of carbohydrates—on postprandial glycemia (22).

The basic premise is that more moderate blood glucose and metabolic responses from low-GI foods and a low GL will sustain satiety and energy balance to a greater extent than would high-GI foods and a high GL load. The GI may be important in regulating hunger, voluntary energy intake, and satiety. A high-GI meal or snack may compromise glucose uptake following a subsequent meal—a phenomenon known as the “second-meal effect.” The underlying mechanism likely involves decreased insulin sensitivity with increased concentrations of circulating free fatty acids during the late postprandial phase. With regard to a high-GI meal or snack, it is thought by proponents that, “the drop in blood glucose during the middle postprandial phase may increase the preference for high-GI foods, leading to repeated cycles of excess hunger followed by hyperphagia that may last for several hours following restoration of euglycemia. These vicious cycles, exacerbated by the second-meal effect may contribute to disappointing long-term weight control with conventional low-fat diet prescriptions that emphasize the importance of consuming starchy foods” (22). Hence, low-GI foods are thought to help minimize blood glucose fluctuations, hunger hormones, and increase satiety.

As of today, selecting carbohydrate sources to reduce GI – either without altering the contribution of carbohydrate to total energy or in combination with a decrease in carbohydrate consumption – is a promising but unproven weight loss strategy for obese and overweight individuals. However, most of these studies are short-term interventions, typically less than six months without more significant follow-up. Some studies have conducted a follow-up period at 12 months showing that overweight or obese individuals on low-GI diets loose more weight than those on high-GI diets or conventional energy restricted weight loss diets. Beyond short term weight loss, low-GI diets have also shown to decrease fasting glucose and insulin levels, reduce circulating triglycerides, and improve blood pressure (22;116;117). Thus, low-GI and low-GL diet plans do appear to help individuals lose weight, typically one to two BMI units, and help improve metabolic parameters and risk of cardiovascular disease. However, results are often based on associations, and long-term effects of these diet interventions are unknown (116). The effects of low GI carbohydrates may also help to prevent excess weight gain. However, before low GI diets can be advocated as a weight-loss strategy, more research must be done on their longer-term efficacy (118-120).

Consumption of whole grains, legumes, fruits, vegetables, and whole foods that are low in GI, is helpful in meeting fiber goals and may be helpful in weight management. A well balanced, hypocaloric low glycemic index diet may prove to be effective in properly educated, adherent patients who do not misuse it by consuming excess fat or protein, or by completely excluding healthful high glycemic foods. For example, sausages, ice cream, and chocolate cake with frosting are all low GI foods, while parsnips, carrots, bananas, dates and potatoes tend to be high GI foods. This underscores the point that more than just GI must be considered in food choices and patients beed to be educated accordingly. It is still unclear if the glycemic index offers sustained advantages to patients in planning menus and in learning to control food intake compared to other weight reduction methods, especially since GI is not listed on most food labels, and many factors influence it, such as cooking, ripeness, and the other foods consumed at the same meal. Any reducing diet must be viewed as a whole. In the USA nutrient fact labels are available on most processed foods, and provide information on carbohydrate content, however, this is not the case in some countries where GI is popular. Focusing on only one aspect whether is the glycemic index, the sugar content, carbohydrate, fiber, protein or fat is not a solution in itself.

In terms of weight loss, those on GI based diets fare as well, if not better, than those following a conventional restricted low fat diet. Furthermore, overweight or obese people on low GI diets lose more weight along with subsequent decreases in BMI and total fat mass than those on high GI diets or conventional energy restricted weight-loss diets (121). However, the data is limited in US populations. In summary, diets based on the GI may offer some patients benefits in terms of short and long term weight loss, but the perpetuity of the regimen remains in question.

9.4.4 High-Fructose Corn Syrup and Weight

High-fructose corn syrup (HFCS) does not contribute to overweight or obesity any differently than do other energy sources (122). HFCS wrongly received blame for the obesity epidemic simply due to the association between American’s increases in weight along with the increase in HFCS in our food supply since the 1970s. In 2004, Bray et al (123)hypothesized that HFCS was a direct causative factor for obesity. However, to date, there is no scientific evidence supporting this theory. As stated in White’s article from The American Journal of Clinical Nutrition, “The HFCS-obesity hypothesis of Bray et al relies heavily on the positive association between increasing HFCS use and obesity rates in the United States. However, Bray et al treated this association in isolation, offering no perspective on trends in total caloric intake or added sweeteners use in comparison with use of other dietary macronutrients.”

HFCS was introduced to the food industry in the late 1960s and was well received because it is stable in acidic foods and beverages, is easily transportable and is sweet. HFCS can be pumped from delivery vehicles to storage and mixing tanks, requiring only simple dilution before use. Furthermore, it has remained relatively inexpensive. Its sweetness mirrored that of sugar. Contrary to popular belief, HFCS is not sweeter than sucrose. The forms of HFCS in the food supply are HFCS-55 and HFCS-42 with 55% fructose and 42% glucose, and 42% fructose and 53% glucose, respectively. The remaining carbohydrates are free glucose, maltose, and maltotriose. A similar ratio of fructose to glucose as in HFCS is also in honey, invert sugar, fruit, and fruit juices (124). Table sugar or sucrose is composed of 50% fructose and 50% glucose. Hence, the ratio of glucose to fructose in both HFCS and sucrose is essentially 1 to 1. Furthermore, HFCS and sucrose both contain four calories per gram. Fundamentally, there is no difference between the compositions of the two

Proponents of the hypothesis that HFCS is a causative factor for obesity often claim it is due to metabolic differences between fructose and glucose: fructose is taken up by the liver and bypasses a key regulatory step in glycolysis. However, White stated, “The inability of the body to distinguish fructose-containing nutritive sweeteners from one another once they reach the bloodstream is critical to the HFCS discussion, but often overlooked. Sucrose, HFCS, invert sugar, honey, and many fruits and juices deliver the same sugars in the same ratios to the same tissues within the same time frame to the same metabolic pathways. Thus, if one accepts the proposition that a given product will be sweetened with one of the fructose-containing nutritive sweeteners, it makes essentially no metabolic difference which one is used (124).” HFCS-55 is 55% fructose and 42% glucose, HFCS-42 is 42% fructose and 53% glucose, and sucrose (table sugar) is 50% glucose and 50% fructose. According to Melanson et al, the evidence suggests that high consumption of pure fructose may be problematic regarding metabolic regulation. However, HFCS is more similar to sucrose than it is to fructose in terms of its content, appetitive responses, and aspects of its metabolism that have been measured to date. Existing theoretical and empirical evidence suggests that fructose-induced problems are not more related to HFCS than sucrose intake (125).

HFCS is not a direct cause of the obesity epidemic in the United States. To date, there is no evidence linking these two factors (122;126;127). As Forshee et al concluded, “Evidence from ecological studies linking HFCS consumption with rising BMI rates is unreliable. Evidence from epidemiologic studies and randomized controlled trials is inconclusive. Studies analyzing the differences between HFCS and sucrose consumption and their contributions to weight gain do not exist. HFCS and sucrose have similar monosaccharide compositions and sweetness values. The fructose to glucose ratio in the United States food supply has not appreciably changed since the introduction of HFCS in the 1960s. It is unclear why HFCS would affect satiety or absorption and metabolism of fructose any differently than would sucrose. Based on the currently available evidence, an expert panel concluded that HFCS does not appear to contribute to overweight and obesity any differently than do other energy sources” (122).

9.5 Water

This section discusses water and electrolyte needs during weight reduction.

9.5.1 Water Needs on Reducing Diets Vary

Ample fluid intake is important on weight reduction diets to prevent dehydration, especially if diets are ketogenic, very low in calories, or being undertaken in hot climates or with physical exertion. As mentioned earlier, losses of body glycogen and protein are accompanied by losses of body water. Intake of low-calorie or calorie-free fluids such as water should be emphasized (128). Water needs go up with increases in physical activity, not only due to sweat losses, but also due to increased water losses due to aspiration (50).The fatigue that some dieters associate with hypocaloric diets is often due in part to dehydration, especially if they have also increased their physical activity and exercise regimes dramatically. Body water losses of as little as 2% have been associated with decreased physical and mental performance, and impaired thermoregulation (128). General water recommendations average approximately 2.7 liters (91 ounces) per day for women and 3.7 liters (125 ounces) per day for men. This includes total water intake from all beverages and water in foods. It has been estimated that 20% of total water consumption comes from solid foods (129). A fluid intake plan should be incorporated in every weight loss regimen.

9.6 Electrolytes

Under normal circumstances on a well-balanced diet that is not overly restrictive with energy, electrolyte balance is maintained. If an individual may be losing excess electrolytes due to high sweat losses, electrolytes can usually be replaced with normal foods (50). The American diet is overly abundant in sodium. Potassium is not so abundant but can be obtained in fruits and vegetables. Examples of foods that are high in both sodium and potassium include tomato sauces and vegetable soups.

Electrolyte levels are of particular concern on VLCD, since occasionally cardiac arrhythmias have resulted from hypokalemia on such regimens (83). Since hypokalemia can be fatal, electrolyte levels must always be monitored on VLCD.

9.7 Vitamins and Minerals

The next section outlines vitamin and mineral needs during weight reduction.

9.7.1 Vitamin and Mineral Needs During Weight Reduction

Vitamin and mineral nutrition is critical during weight reduction and maintenance. The Recommended Dietary Allowance (RDA) for an individual’s age and sex must continue to be met, even on reducing diets for all other nutrients (See Table 14and Table 15). The lower the diet is in calories, the more likely it is that essential vitamins, minerals and electrolytes such as potassium, copper, magnesium, Vitamin E, Vitamin B6, folic acid, iron, and calcium are likely to be low. As a rule of thumb, diets below 1,200 calories per day are likely to require vitamin and mineral supplements in amounts approximating the Recommended Dietary Allowances (13). Above 1,200 calories per day, women in reproductive age groups may still need iron, calcium, and folic acid supplements, since their needs for these nutrients are high, but most other nutrient needs can be met by a well-balanced diet that follows the Dietary Guidelines for Americans (13). For this reason, foods with high micronutrient density, but low energy density are especially important to include on a reducing diet. They include fruits, vegetables, legumes, and lightly processed whole grains. Table 14, Table 15, Table 16, and Table 17present the current DRIs for vitamins, minerals and tolerable upper levels (UL) for these same nutrients.

9.7.2 Calcium Supplementation, Dietary Dairy Intake, and Weight Loss

Some studies in the past have suggested that calcium supplementation and/or supplementation of dairy products in the diet play a direct role in the prevention and treatment of obesity. However, recent randomized clinical trial evidence does not support this hypothesis. Studies have found that calcium or dairy consumption do not aid in weight loss (131), nor does calcium supplementation have an effect in preventing weight gain (132-134).

In a review evaluating 49 randomized clinical trials assessing the effect of dairy product or calcium supplement consumption, 41 studies showed no effect, two reported weight gain, one showed a lower rate of gain, and only five showed it was effective as an aide in weight loss (131).

Major et al found that calcium plus vitamin D supplementation enhanced the beneficial effect of weight loss on the lipid profile; however, it had no effect on weight itself (135). There is also some evidence that high calcium or high dairy intakes during weight loss spare lean tissue loss to a greater extent than lower levels, although the evidence is not conclusive at this time.

9.7.3 Dietary Supplements and Weight Loss

Seven percent of adults in 1998 used over the counter (OTC) weight-loss supplements, with the greatest use noted among young obese women (136). Retail sales of weight-loss supplements were estimated to be over $25,177 billion in 2008, including meal replacements (137).

In 2001, MetaboLife® 356, an Ephedra-containing combination supplement, was the top selling dietary supplement, it reached $70 million in sales, but it was also responsible for 64 percent of all herb-related adverse events reported to the U.S. Poison Control Center during that same year (136;138). Ephedra, or Ma Huang, is the common name for the herb that was used in many of these weight loss supplements. It is an herb used in traditional Chinese Medicine (TCM). Its use in weight reduction though, is not a common practice in TCM. Americans used this supplement as a weight loss aid from the mid 1990’s, up until 2004, when it was banned by the FDA (139;140).

The NIH sponsored a thorough systematic review of the safety and efficacy of Ephedra through the Agency of Healthcare Research and Quality’s (AHRQ) Evidence Based Practice Center at the University of Southern California, which conducted the study. It concluded that the use of Ephedra, with or without caffeine, correlated with a small but nonetheless statistically significant increase in weight loss over six months, (almost equal to 0.9 kilograms per month more than with the placebo). The weight lost by those taking Ephedra in combination with caffeine exceeded weight lost by prescription medications in two head-to-head randomized, double-blinded clinical trials (139). There were no studies that measured the long-term effects (more than 6 months) of Ephedra use, and the problem was that the supplement was not safe. Adverse effects of the supplement in the AHRQ study included two to three times more nausea, vomiting, psychiatric symptoms such as anxiety and change in mood, autonomic hyperactivity, and palpitations when compared with placebo. Serious adverse events (SAE’s) were defined as specified by FDA criteria. SAEs were reported to the FDA, and adverse event reports from a manufacturer of Ephedra-containing dietary supplements were also evaluated in the RAND/Southern California systemic review. These reports raised concern about the safety of dietary supplements containing Ephedra due to the number of deaths, myocardial infarctions, cerebrovascular accidents, seizures, and serious psychiatric illnesses in young adults, data was sufficient to warrant concern (139).

The FDA concluded in 2004 that Ephedra-containing products were not to be recommended for weight loss. There was unreasonable risk for illness and injury when taking such dietary supplements. Thus, the sale of dietary supplements containing Ephedra has been prohibited in the United States since April 2004 (139). Ephedra like supplements such as Citrus aurantium (Bitter orange) may also pose risk.

The latest information on dietary supplements and weight loss can be found at www.ods.nih.gov.

9.8 Fiber

The next section outlines dietary fiber needs during weight reduction.

9.8.1 Fiber Needs in Reducing Diets

Dietary fiber is chemically similar to carbohydrate in most of its forms but it is virtually non-caloric because the human body lacks the enzymes to break the fiber’s glycosidic bonds. Some short-term experimental and several cross-sectional studies suggest that an increased dietary fiber intake reduces weight gain. In contrast, fiber is not effective as a weight loss aid (141). Fiber should be included in the LCD reducing diet at levels of about 25 to 38 grams per day to facilitate laxation. Both soluble and insoluble dietary fiber may also modify hunger and help to sustain satiety, but again experimental evidence is not conclusive (8;142;143). Inclusion of five or more servings of fruits and vegetables daily, with plenty of whole grain breads and cereals helps to meet both soluble and insoluble fiber goals on reducing diets. On a VLCD, it is also important to include at least some fiber. As dietary fiber intakes increase, water requirements also increase, so intakes of fluid should also be substantial. Adequate fiber and water are essential for maintaining a soft stool and normal laxation. Ample fiber intakes are associated with reduced risk of several chronic diseases (144).

9.9 Energy-Dense Beverages, Alcohol, and Energy-Free Artificially and Naturally Sweetened Beverages

Currently, it is estimated that the mean intake of added sugars in the American diet is about 15.8% of total energy, and that the largest source of these added sugars is from calorically sweetened beverages such as soft drinks, fruit aides, and other sweetened beverages. These calorically dense beverages account for 47% of total added sugars in the diet (145;146). The term “energy-dense beverage” encompasses a wide variety of beverages, including soda, fruit drinks, juice, lemonade, iced tea, milk and soy beverages, and alcohol.

9.9.1 Energy-Dense Beverages

When compared to water or energy-free beverages, consumption of energy-containing beverages tends to increase total energy intake from meals (145). Although the evidence is not highly conclusive, it is argued that 1) consumption of an isocaloric beverage compared to consumption of solid food prior to a meal increases food intake, 2) solid foods influence satiety hormones, whereas energy-dense beverages show less satiating efficiency, and 3) energy-dense beverages are often comprised largely of refined carbohydrates, which stimulate fewer satiety signals than unprocessed carbohydrates, fat or protein (145). More research is needed on this issue. It should be noted that alcohol is also energy dense. This is discussed below further in section 9.9.2 Alcohol.

The Beverage Guidance Panelrecommends that the average person limit daily consumption of caloric, sweetened beverages without nutritional benefits (soft drinks, fruit drinks, fruit cocktails, fruit aids, and sweetened teas and coffees) to eight ounces per day. Caloric, nutrient-dense beverage consumption (milk, soy and 100% fruit and vegetable juices) should be kept to a minimum (147). In the United States, a regular, 12-ounce can of soda provides approximately 150 calories, typically in the form of high-fructose corn syrup. These calories, if not balanced with exercise or a caloric reduction in other areas of one’s diet, could lead to a weight gain of 15 pounds (6.75 kilograms) in one year (148).

While there may be health benefits to consuming energy and nutrient dense beverages such as milk and 100% fruit juice, the additional energy provided by these beverages must be offset by an increase in energy expenditure or a decrease in other areas of energy consumption in order for weight loss or weight maintenance goals to be achieved. For this reason, energy-dense beverages are generally not recommended for patients attempting to lose weight.

9.9.2 Alcohol

Alcohol (ethanol) contains approximately seven calories per gram, providing more energy per unit of weight than either carbohydrate or protein (each providing about four calories per gram), but less than fat (about 9 calories per gram). Alcoholic beverages are a source of non-nutritive energy, or "empty calories". If protein, carbohydrate and/or fat are consumed at the same time as alcohol is ingested, their oxidation will be suppressed (most notably fat oxidation), since alcohol is preferentially oxidized, and the other macronutrients balance through the sparing effect of alcohol on fat oxidation, this may lead to increased fat storage.

In addition to alcohol’s influence on macronutrient metabolism, chronic excess intake of alcohol also interferes with the absorption and utilization of several vitamins and minerals. Alcohol in excess also impairs nutrient absorption by damaging the stomach and intestinal lining, disabling the transport of some nutrients into the blood. Chronic overconsumption of alcohol can also lead to fatty liver, dyslipidemia, and further weight gain, and should be discouraged.

Another important consideration concerning alcohol’s influence on energy balance is its effects on energy intake. Alcohol is positioned at the bottom of the hierarchy of satiating efficiency of metabolic fuels consumed by humans (8). Generally, fuels satiate to degrees from lowest to highest: alcohol, fat, carbohydrate (depending on type), and protein (149). Alcohol energy is additive to the diet, producing no compensation in energy intake under most ad-libitum situations, and in fact, some research suggests that alcohol may stimulate appetite (150;151). For these reasons, alcohol consumption is usually contraindicated on weight-loss diets.

9.9.3 Energy-Free Artificially and Naturally Sweetened Beverages

Energy-free, artificially sweetened beverages are consumed by approximately one fifth of U.S. adults (152). In human studies, data are conflicting on whether they are associated with weight loss (153).

The FDA has approved six non-nutritive sweeteners for use in foods and beverages in the United States to date, including acesulfame-potassium (Acesufame-K. Ace-K, Sunett, Sweet One), aspartame (Equal, NutraSweet), neotame, saccharin (Necta Sweet, Sugar Twin, Sweet ‘N Low), sucralose (Splenda), and the newest, plant-derived sweetener, stevia (PureVia, Sun Crystals, and Truvia). The FDA also recently granted the product Fruit-Sweetness™Generally Recognized As Safe (GRAS) status, making it the first all-natural zero-calorie fruit concentrate sweetener to be GRAS notified by the FDA. Fruit-Sweetness™is a fruit concentrate derived from the monk fruit, a traditional fruit originating from South East Asia (154).

For weight management, energy-free artificially/naturally sweetened beverages are a preferable alternative to energy-dense high calorie beverages, such as regular soda and alcohol. Some recommend that adults consume no more than 32 ounces of artificially sweetened beverages per day, but there is little evidence for this recommendation (147).

9.10 Energy Density

Energy density, or caloric density, is defined as the calories provided per unit weight of food eaten (such as calories/gram). When the composition of a diet of usual foods is decreased in fat, the energy density of the diet tends to fall since the total weight of food consumed remains constant (155-157). Some of the beneficial effects of low fat diets in weight loss and maintenance may be due to low energy-density, rather than to decreased caloric energy from fat itself. Furthermore, foods high in water and/or fiber tend to have low energy density, with some that are very high in volume, such as unbuttered popcorn. Their inclusion in a weight reduction diet is advocated by some experts for this reason (8). As will be discussed later, some evidence suggests that low-energy density, high-volume diets may help people ingest fewer calories and thus may assist with weight loss, although longer-term research is needed.

10 Available Programs

According to the U.S. Food and Drug Administration (FDA), Americans spent an estimated $30 billion in 1992 on diet and weight loss programs. Marketdata, an independent of the U.S. weight loss industry, estimated spending to have reached over $60 billion by 2008 (158). The number of products is endless, and the quality, questionable. Patients should be advised to research programs they are interested in, and consult with a physician before participating in them.

10.1 Registered Dietitians: Dietetic Advice and Individualized Eating Plans

A registered dietitian is a food and nutrition expert who has met academic and professional requirements including:

• A bachelor's degree at an accredited university, approved by the Commission on Accreditation for Dietetics Education (CADE) of the American Dietetic Association (ADA).

• Completed an accredited, supervised, experiential practice program (dietetic internship) at a health-care facility, community agency, and/or foodservice corporation, including at least 900 hours of hands-on experience.

• Pass a national examination administered by the Commission on Dietetic Registration (CDR).

• Complete continuing professional education requirements to maintain registration.

Many physicians lack the time that obese patients require for successful weight control therapy. Referral for dietary counseling to a registered dietitian (RD) is useful for many patients, particularly those who have comorbidities that also require medical nutrition therapy. Many registered dietitians also hold certifications in specialized areas of practice, including weight management, providing additional expertise in the management and treatment of obesity (159). They are able to understand therapeutic dietary recommendations beyond simple weight loss diets that many people require. Practicing registered dietitians in your area can be located using the website for the American Dietetic Association at http://www.eatright.org/.

10.1.1 Available Programs

There are over 67,000 registered dietitians in the United States, practicing in hospitals, outpatient centers, health centers, the community, and in private practices, among many other areas of expertise. Patients can see a registered dietitian via patient referrals from physicians for a variety of health problems that require dietary modification, or by self-made appointments. Depending on the area of dietary modification/treatment, health insurance may, or may not, cover the services provided, so patients need to check with their insurance providers before scheduling an appointment. Some formal weight control programs staffed by dietitians are available in hospitals and health centers, where individual counseling is also available.

10.1.2 Candidates for Care

Dietary advice of a general nature is not enough for patients who have multiple comorbidities requiring medical nutrition therapy (e.g., diabetes, hypertension, coronary artery disease, gastrointestinal disorders, etc.) or other medical or surgical intervention, those on multiple medications, and those with complex and involved health problems that have dietary implications. These patients are prime candidates for dietetic therapy and help from a dietitian. Patients who have had poor outcomes in weight control efforts on their own, who have special dietary needs or preferences, and who need extensive education and assistance are also particularly likely to benefit.

10.1.3 Advantages

Registered dietitians are able to read and interpret medical records and are equipped to adopt weight loss prescriptions to the particular needs of patients. Their knowledge of food habits, food preparation, and food products on the market makes them a good resource for helping patients to adopt the general weight control prescription to the patient’s particular circumstances. A particular advantage of dietetic involvement in patient care is that dietitians often work in medical settings and have access to patient charts as well as to consultation with other health professionals. Registered dietitians are helpful for dealing with patients on multiple medications, on very-low-calorie diets, and post-gastric bypass counseling. Some dietitians have advanced certification in weight management, and are especially well equipped to counsel patients with complex and involved medical problems. Some insurance companies and health maintenance organizations may pay for obesity treatment when it is part of a larger therapeutic program for diabetes or some other conditions if it involves a dietitian who is a certified Medicare provider. Patients should check with their insurance providers about reimbursement.

10.1.4 Disadvantages

The patient’s out-of-pocket costs for dietary counseling from a registered dietitian vary, depending on insurance coverage and the comorbidities that need to be treated/addressed. Note that personal trainers and/or nutritionists do not necessarily have the credentials to be counseling patients.

10.1.5 Safety and Effectiveness of Therapy

Registered dietitians are health professionals who go through extensive schooling and training and are registered in a national registry with specific standards. Licensure is also required in 31 states, and as such, many dietitians are licensed in most states in addition to their registration status. As such, they have medical, legal, and ethical obligations to their patients. They often have access to patient medical records. Their own education includes formal educational requirements of at least a baccalaureate degree, a dietetic internship, supervised clinical training, a registration exam, and mandatory continuing education. Dietitians are trained to read medical charts, to work with physicians and other allied health professional, and to alert physicians when untoward events arise. Thus their recommendations regarding weight loss tend to be safe. The effectiveness of dietetic counseling, like that of physician counseling for weight control, has seldom been evaluated. The American Dietetic Association, the dietetic professional association, is currently developing and testing clinical guidelines for weight reduction and management of various obesity-related conditions.

10.2 Commercial Weight Loss Programs

Commercial non-medical weight control programs are popular and widely available in the United States and Canada.

10.2.1 Available Programs

Commercial programs include large chains such as Weight Watchers®, Jenny Craig®, LA Weight Loss Centers®, Nutrisystem®, Curves®, and many regional ventures. These programs vary, but generally include advice on a structured low calorie diet, exercise, lifestyle modification coupled with group support and/or individual counseling. Usually the program is administered by a layperson trained by the program who is often a successful program graduate. However, laypersons trained by the company and degree-trained professionals (such as dietitians) may also be on their staff. It should be noted that these programs do not provide physician supervision although they usually require physician sign-off before involvement (83). All of these programs are for-profit entities and charge fees (155).

10.2.2 Candidates

Overweight and moderately obese persons with few risk factors and few comorbidities are good candidates for these programs. Those who find that they need continued motivation, monitoring and social support with a structured regimen may particularly benefit from the program.

10.2.3 Appropriate Use

These programs are not substitutes for physician concern or medical monitoring of his or her patients’ weights. They are most successful when the patient’s personal physician continues to provide encouragement and supervision because most commercial weight loss programs provide no or very little physician supervision. The commercial programs are not equipped to deal with patients with multiple involved comorbidities of either a medical or psychological nature. Those patients are better treated by a program and therapists who are more closely connected to the health care system where medical charts and other patient-specific information is available. Registered dietitians and specialized weight control programs operated by medical facilities are such options.

10.2.4 Advantages

Most major established commercial chains offer well crafted, nutritionally adequate and behaviorally sound programs that are reasonable therapies. Classes are often held in places of employment or neighborhood centers that are conveniently located. Weight Watchers® offers frozen entrées and other weight control products that are keyed into the program and available in the supermarkets, making adherence easier. Jenny Craig® and LA Weight Loss Centers® also offer frozen entrees and various weight control products; however, these are only available through their stores. Lastly, if on Nutrisystem®, the customer must eat only Nutrisystem® food for a defined period based on individual needs. Nutrisystem® sends all food items including snacks to the customer via mail.

In a multicenter, randomized, two-year study of 423 subjects with a BMI of 27 to 40 kilogram/m² it was shown that a structured commercial weight-loss program was more likely to be effective for managing moderately overweight patients than brief counseling and self-help (160). Individuals were randomly assigned to either a self-help program, consisting of two 20-minute sessions with a nutritionist and provision of printed materials and other self-help resources, or to attendance at meetings of a commercial program (Weight Watchers®). After 26 weeks subjects in the commercial weight-loss program had greater decreases in body weight, BMI, mean waist circumference, and fat mass (160). It is important to discuss commercial program options with individuals so they know their options, but only with individuals who are plausible candidates.

Since it was founded in 1997, most of the large commercial programs have joined the Partnership for Healthy Weight Management, a voluntary association. Members provide, on a voluntary basis, publicly available information to help potential participants meet their needs. Criteria for membership require that programs disclose staff qualifications, essential components of the program, the risks associated with overweight and obesity, other details about the provider’s program or product, and program costs.

10.2.5 Disadvantages

The main objective of a commercial weight loss programs is profit and not patient care. Although physician approval is required by most programs before participants can enroll, there is no guarantee of the quality of the health assessment that has been carried out prior to enrollment. For some individuals, especially those at very high risk, more intensive medical supervision may be required. The cost of the programs is another obstacle. Many of the poor who are obese do not have the resources to purchase these services and products, even though they might benefit from them. Discounts or waivers of fees for those in financial hardship are rarely available.

Statistics are rarely kept on success rates or long-term adherence. Another problem is maintenance of lost weight and preventing relapse. The companies have become more active in developing programs catering to those who have lost weight to help them maintain their losses in recent years, but incentives to patients for staying in maintenance programs may still not be sufficient. Additionally, very few high-quality studies have assessed the efficacy of commercial weight loss programs and the ones that do provide the best-case scenario for results—as they do not account for participants who have dropped out of the program (161). The only program that has published high-quality studies to date is Weight Watchers®. The best study on Weight Watchers® determined that participants lost 5% of their initial body weight (about 10 pounds) in 6 months and kept off 3% (about five pounds) at two years (161).

10.2.6 Effectiveness and Safety

The major firms provide programs and products that are safe when directions are followed. However, in spite of the fact that millions of Americans have purchased these services, their effectiveness in bringing about weight loss or sustaining lower weights has rarely been studied with scientific rigor (83).

10.3 Formulas and Meal Replacements

Many meal replacement and formula products for weight control are now available which patients can purchase on their own in supermarkets and drug stores. Unlike very low-calorie diet formulas, which are medical foods that are usually provided as part of a medically supervised treatment program (see Table 13), these products can be purchased by anyone.

10.3.1 Available Products

Meal replacements now include not only powders like Slim-Fast® that are mixed with milk or other liquids, but drinks, bars, and frozen entrees. Formulations and nutrient content vary. Most liquid meal replacement products provide about 220 calories per serving and are relatively high in protein, vitamins and minerals, but low in fat (see Table 19for examples of over-the-counter, ready-to-drink, liquid meal replacements). The health bars and frozen entrees vary in their caloric content, but are generally between 200 and 400 calories, and have more complete profile of nutrients than most other single foods. The entrees include offerings such as Lean Cuisine®, Healthy Choice®, and Smart Ones®, among others (see Table 20for product listing). All of these pre-packaged entrees share characteristics such as discrete portion sizes that are relatively low in calories (usually 300 calories or less) (See Table 20). Generally, all frozen entrees are high in sodium with at least 500 mg of sodium per serving. Smart Ones® is manufactured by HJ Heinz, and is closely allied with the Weight Watchers®commercial diet program. Its packages are prepared to fit into the food plans for the Weight Watchers®program. All of the meal replacement products are designed to be eaten with additions of conventional foods that supply dietary fiber, other nutrients, additional calories and fluids.

10.3.2 Candidates

Individuals who are healthy but moderately overweight (BMI 25-30) and who wish to lose less than 5% of their body weight or who wish to use these products for one meal a day to assist in their weight maintenance efforts may find these products helpful. The products provide an easily prepared, generally nutritious, and relatively modest caloric load that slakes hunger. For those who are susceptible to environmental triggers (such as being involved in meal preparation, eating in cafeterias or fast food restaurants) and respond by overeating, these products offer a safe and palatable option that lessens temptation.

10.3.3 Appropriate Use

Portion controlled liquid meal replacements such as Slim-Fast® (and many other products) are recommended for two meals and a snack with a small meal of conventional foods and low or no calorie beverages. They should not be used as the sole source of nourishment on a diet. The entrée choices are suitable for lunches and/or dinners.

10.3.4 Advantages

The main advantages of meal replacements are built-in portion and calorie control, widespread availability, convenience composition that is fairly micronutrient dense while remaining low in calories, ease of preparation, and for some of the dry or canned products portability. Also, costs of the meal replacements are reasonable and simplify food choice decisions. They are lower in calories than many snack foods that people who are eating away from home might substitute for them. Also, they are convenient, rapidly and easily prepared options that can be eaten anywhere, allowing eaters to avoid "high risk" eating environments.

10.3.5 Disadvantages

The major disadvantages of these products are their cost, monotony, low taste, and limited variety. From the nutritional standpoint, the products vary, but are often quite high in sodium (600 plus milligrams per serving). Only Healthy Choice®is low in calories, saturated fat, and also in sodium. As with most strategies, they are ineffective unless they are used as part of an overall low calorie eating plan. If they are used as sole sources of food they would be nutritionally inadequate not only in energy, but several other nutrients and water. Additionally, they might not provide the dieter with practice in planning and preparing their own healthy low-calorie meals for a lifetime of healthy weight management. However, there is little evidence on this part.

10.3.6 Effectiveness and Safety

These products may be nutritionally inadequate when they are used as the sole sources of food and fluids for many weeks. When the products are used according to directions on the label or in package inserts, they are safe (54). When used as part of a weight loss program these single meal replacements are effective during the weight loss phase (157). They are also valuable additions in the weight maintenance phase, often because the meal replacements provide a low set number of calories in an easy-to-fix-entrée (4;149), with control over portion size(162).

10.4 Prepared Delivered Meals

Commercial catering operations in many parts of the country have begun to offer prepared, delivered meals directly to consumers. Nationwide franchises such as Nutrisystem®and Jenny Craig®offer prepackaged, frozen meals to aide in weight loss. These programs allow participants to choose meals (breakfast, lunch, and dinner) based on taste preferences, while also offering the freedom of convenience with home delivery.

10.5 Weight Loss Books and Manuals

In addition to weight loss products, Table 21provides some examples of popular diet books. Books are difficult to use on one’s own because there is little reinforcement. The quality of self-help books on weight control ranges from the sublime to the ridiculous. Among the better, older books currently on the market are the LEARN® Program for Weight Management, which is a sound 15 week course that is usually administered within a treatment program (94;159). The book is effective when it is part of the treatment program. However, the charges for such a program are considerable, the program is not available in all parts of the country, the effectiveness of self directed efforts using the book by itself has not been evaluated, and the dietary advice is often vague. Another good book is Volumetrics by Barbara Rolls PhD (163), which encourages a diet based on foods that have a low energy density, meaning that they contain few calories per gram of weight. Dr. Rolls’ research has shown that foods with large volume but few calories can provide satiety while helping individuals avoid over-consumption of energy. Such foods are usually high in water and fiber, while low in fat. Although the long-term efficacy of this specific diet has yet to be affirmed, the diet is rich in fruits, vegetables, and other healthful foods (163).

10.6 Web-Based Treatment Programs and Resources

The internet provides some excellent resources for those who want and need more information. However, it also includes sites with questionable recommendations, so individuals should proceed with caution.

10.6.1 Available Programs

Two types of programs are available. First are those that primarily provide information. Second are those that counsel the individual and provide low calorie diets and other advice. Sound internet resources that can help those who are trying to control their weights are listed in Table 22. These fall into the category of informational resources. The reader needs to beware that not all sites providing advice and information are sound. It is best to trust the sites sponsored by government, professional, and voluntary associations with some standing and expertise in the weight control field. A new entry into the weight loss arena in recent years is the web-based weight control program (164).These are examples of the second type of program. Resources include chat rooms, diet and exercise information, and often products that are for sale. For example, Nutrisystem®.com requires the purchase of prepackaged foods as well as providing a web site. The e-diet.com website, another weight control program, charges for a visit to its site. It provides shopping lists from which consumers self select foods, and also it provides general advice.

These web-based commercial offerings vary in their quality, some are very good and others are poor (54).

10.6.2 Candidates

Those who are overweight or moderately obese with few risk factors and who need additional support and information after they have been screened by a physician on weight reduction may find these resources useful. They are not freestanding and need to be administered in conjunction with some additional health and dietary counseling about a hypocaloric diet from a physician or registered dietitian.

10.6.3 Advantages

The internet is widely available at all times of the day or night, at low cost. For example, the US Army has developed a web-based dietary advice program that can be used at Army bases around the world.

10.6.4 Disadvantages

High risk patients, especially those who lack economic resources, may attempt to use these internet sites for the primary treatment of their condition. Also some sites provide inappropriate or wrong advice. There is little personal supervision or support of the dieter.

10.6.5 Safety and Effectiveness

The safety and effectiveness of internet sites for weight reduction has not been established (83). Only recommended sites should be trusted.

10.7 Voluntary Self-Help Programs

Self-help programs led by laypersons are voluntary programs that charge very low or no fees. National organizations include TOPS Club, Inc.® (Take Off Pounds Sensibly), OA (Overeaters Anonymous®), and others. These programs are designed primarily to provide group support to those who have weight problems, rather than to provide and supervise weight reduction diets.

10.8 Mobile Applications for Weight Loss

As people’s lives become more mobile, so do tools to help them in weight loss. Calorie tracking programs are available to monitor daily intake (such as Calorie Trackerand Lose It!for the iPhone)and fitness programs provide sample workouts and activity logs (like iPump Free Workout, StepTrackLite, and iMapMyRunfor iPhone). A full list of mobile applications for the iPhoneand the Blackberrycan be found online (http://www.apple.com/iphone/apps-for-iphone/and http://appworld.blackberry.com/webstore/, respectively).

11. Summary of Weight Loss Phase

Current guidelines for the composition of weight reducing diets, as discussed above, are outlined in the 2005 Dietary Guidelines for Americans (Table 1), as well as the MyPyramid.gov website.

12. Weight Maintenance Phase of Weight Control

Once the obese individual has lost body fat, his or her healthier weight and fatness studies must be maintained. Thus, the energy deficit phase of weight control is followed by the weight maintenance phase. It involves alterations in dietary intake and physical activity from levels prior to the onset of the dietary treatment. Paradoxically, the slimmer individual’s energy needs are lower to stay in energy balance than they were prior to weight reduction. The primary reason for this is that some loss of lean as well as fat tissue inevitably occurs on reducing diets. Metabolically active tissue is reduced and resting metabolism is decreased after weight loss. Also, it takes less effort to move the lighter body, so the energy cost of physical activity is thus reduced. The implications are that a slight decrease in energy intake from prior levels and an increase in energy output will be necessary during weight maintenance. There is a need for continued attention to these factors on the part of the physician and patient. Behavior modification necessary to sustain these lifestyle changes is best practiced during the weight loss phase, and maintained thereafter. All too often the weight maintenance phase is neglected or ignored, and weight is regained over the long term (54). The best way to maintain energy balance in the face of lower energy needs over the long term is an important question that still has not been answered satisfactorily (168). Some factors that seem to be associated with long-term successful weight maintenance include continued regular exercise and to a lesser extent, use of low calorie, low fat diets relatively high in fruits and vegetables. Also, continued self-monitoring of the amount and type of food consumed and of physical activity levels may help (54).

12.1 Nutrient Needs

Although energy needs are less during weight maintenance, the requirements for protein, essential fatty acids, carbohydrate, dietary fiber, vitamins and minerals are similar to those of any normal adult, and should be provided. MyPyramid.gov’s macronutrient composition provides approximately 24% fat, 18% protein, 59% carbohydrate, and 22 grams of dietary fiber; with advice that added sugars and fats are to be used sparingly (60). The 2005 Dietary Guidelines for Americans recommend that all Americans, including those who are watching their weight, to adopt the following habits (see Table 1).

There is currently much dispute about the ideal macronutrient distribution in diets for weight maintenance, but at present very few long-term studies are available. Little is known about the effects of the diet’s macronutrient content on weight maintenance. However, recent data suggest that a combination of a physically activity, moderation in dietary intake, and appropriate behavior modification are key.

12.1.2 Carbohydrate

A recent study of the self-selected diets of free-living American adults found that diets high in carbohydrate (above 55% of calories) were lower in energy and in the calories per gram of food they supplied and were associated with the lower BMI’s than those consuming less carbohydrate. The nutrient density (amount of the nutrient per calorie consumed) was also higher for vitamins A, Vitamin C, carotene, folate, calcium, magnesium, and iron, but lower in vitamin B-12 and zinc than those with lower intakes of carbohydrates. Also, the high carbohydrate group ate more low fat foods, grain products and fruits and had the lowest sodium intakes of the groups studied(169).

12.1.3 Energy Density

Other studies suggest that energy density of the diet rather that the macronutrient composition of the diet affects energy intake the most markedly (170;171). One review found that low fat, high fiber diets were the most effective in promising weight loss, and that their effects appeared to be associated with their energy density (172), whether this is true in weight maintenance remains to be determined. There may be macronutrient effects on hunger and satiety that operate through endocrine and metabolic mechanisms such as leptin, insulin, grhelin, adiponectin and other hormones only now being discovered that regulate food intake and that differ depending on these dietary characteristics. Additionally, the macronutrient composition of habitual diets also affects health risks, and these must also be considered. Other effects of usual diets on weight maintenance may be genetic. Finally, psychological and behavioral factors may vary on different macronutrient combinations. Currently, these topics are the subject of much debate, but research is needed to clarify what and which nutrient composition is optimal and how best to help people modulate their energy intakes regardless of dietary composition.

12.1.3 Fat

Although much remains to be discovered about the optimal dietary pattern for weight maintenance, a strong case can be made for keeping dietary fat levels below 30% of calories. In studies in which dietary fat was reduced from 35 to 25% of calories with no other recommendations, energy intake was reduced and weight was lost (173). It was estimated that reducing fat by 10% to within the range of 20 to 30% of calories would result in a loss of about 16 grams of body fat a day owing to reduction in energy intakes. However, moderation in caloric intake is also in order, since in studies of free-living humans ranging from dietary changes produced only modest body weight losses of about one to three kilograms (143;174;175). Low fat diets consumed on an ad-libitum basis tend to be high in carbohydrate, but LDL cholesterol decreases, plasma triglycerides tend to normalize, and so do HDL/total cholesterol ratios (176). Finally, weight control may be easier (177).

12.1.4 Dietary Fiber

Although the influence of dietary fiber on energy regulation is still not clear, there is evidence that increases of dietary fiber of about 15 grams appear to be associated with decreased energy intakes and body weight losses of about two kilograms over several months, and the effects may be greater in overweight persons (142). However, these effects are not yet confirmed. Since dietary fiber intakes are currently low, only about 15 grams per day in most Americans, and recommendations are for nearly twice that much, increased fiber levels seem to be appropriate, regardless.

12.1.5 Lessons from Long Term Maintainers: Importance of Increased Physical Activity

Long-term follow-up of health outcomes demonstrates the need for permanent changes in weight toward healthier levels. The relative lack of effects of temporary downward fluctuations underscores the need for long-term weight maintenance. Data collected from individuals successful at weight loss and maintenance have enhanced our understanding of the most effective strategies in the prevention of relapse and long term maintenance of healthier weights. Attention to moderation in dietary intake and the maintenance of high levels of physical activity is vital (178-181). Behavioral and attitude adjustments are also important. Encouraging data suggest that behaviors associated with maintenance of weight loss require less effort and become more pleasurable over time (21). In a recent telephone survey, 48% of individuals who had ever lost more than 10% of their body weight had maintained this loss for at least one year, and 26% had maintained for at least 5 years (182). Although these data are self reported, they suggest progress in the avoidance of relapse and weight gain.

13. Adopt a Long-Term Eating Pattern to Maintain Weight: Adequate Nutrients within Calorie Needs

Most individuals appear to be aware of and use recommended measures, such as increased physical activity, decreased fat intake, decreased food portions, and decreased energy intakes. The problem is that they do so, but not for enough of the time. However, it is also true that dieting efforts often fail, and weight is often rapidly regained, probably negating predicted health benefits. Chronic dieters tend to be food-preoccupied, distractible, emotional, binge-prone, and unhappy, particularly when the diets are very restrictive (183). It is thus important to foster a healthy, balanced, stable relationship with food and diet. Health professionals can play a vital role in helping patients develop such a relationship.

14. Conclusions: Is Dieting Worth It?

About 39% of women and 21% of men in Western countries have ever tried to lose weight, and approximately 24% of women and 8% of men report that they currently are on a "diet". In contrast, about 25% of men and 30% of women report that they are watching what they eat to avoid weight gain or to maintain their weights at current levels (184). Hypocaloric diets to induce loss of body fat therefore appear to be a common component of the weight control efforts of many people.

These realities and disadvantages have rightly led to questions about whether dieting is "worth it", and whether the treatment is worse than the disease. Certainly they suggest that quality of life measures should be included in studies of reducing diets.

This chapter has stressed the role of the dietary treatment of obesity as a part of a comprehensive program of weight control that includes increased physical activity, lifestyle modification, appropriate intakes of nutrients to minimize chronic disease risk, and eating patterns that maximize quality of life. Such dietary treatment in those with mild to moderate obesity helps to decrease risk factors relative to baseline weights after five years. Therefore some health benefit, although it is limited, may be present. However, the health risk/benefit may be negative when dieting entails a cycle of rapid loss followed by equally rapid weight gain. From the standpoint of quality of life and mental health, psychosocial problems do not appear to be inevitable accompaniments of weight loss (184). Therefore, on balance, dietary approaches to obesity management do appear to be worthwhile, if and only if they are viewed as only one component of a long term weight control program to keep weights and risks at healthier levels. Weight control is "Worth it"!