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4 Weight-Loss and Maintenance Strategies The most important component of an effective weight-management pro- gram must be the prevention of unwanted weight gain Dom excess body fat. The military is in a unique position to address prevention from the first day of an individual's military career. Because the military population is selected from a pool of individuals who meet specific criteria for body mass index (BMI) and percent body fat, the primary goal should be to foster an environment that pro- motes maintenance of a healthy body weight and body composition throughout an individual's military career. There is significant evidence that losing excess body fat is difficult for most individuals and the risk of regaining lost weight is high. From the first day of initial entry training, an understanding of the funda- mental causes of excess weight gain must be communicated to each individual, along with a strategy for maintaining a healthy body weight as a way of life. INTRODUCTION The principle of weight gain is simple: energy intake exceeds energy expenditure. However, as discussed in Chapter 3, overweight and obesity are clearly the result of a complex set of interactions among genetic, behavioral, and environmental factors. While hundreds, if not thousands, of weight-loss strate- gies, diets, potions, and devices have been offered to the overweight public, the multi-factorial etiology of overweight challenges practitioners, researchers, and the overweight themselves to identify permanent, effective strategies for weight loss and maintenance. The percentage of individuals who lose weight and successfully maintain the loss has been estimated to be as small as 1 to 3 percent (Andersen et al., 1988; Wadden et al., 19891. Evidence shows that genetics plays a role in the etiology of overweight and obesity. However, genetics cannot account for the increase in overweight observed in the U.S. population over the past two decades. Rather, the behav- ioral and environmental factors that conspire to induce individuals to engage in 79
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80 TABLE 4-1 Benefits of Physical Activity WEIGHT MANAGEMENT Benefit Improved maintenance of lost weight Reference Pavlouetal., 1989a, 1989b;Phinney, 1992; Skender et al., 1996; Wadden, 1993; Wing, 1992; Wing arid Greeno, 1994 Calles-Esearldon arid Horton, 1992; Wad- den, 1993 Calles-Eseandon and Horton, 1992 Preservation of lean body mass Improved cardiovascular, respiratory, and museuloskeletal fitness Improved psychological profile arid self- esteem Improved mood Improved plasma blood glucose levels, blood pressure, and blood lipid and lipoprotein values Reduced risk for morbidity and mortality ACSM, 2000 Wadden, 1993 Calles-Esear~don and Horton, 1992; Pate et al., 1995; Pavlou et al., 1989a, 1989b Blair, 1993; Dyer, 1994; Pate et al., 1995 too little physical activity and eat too much relative to their energy expenditure must take most of the blame. It is these factors that are the target of weight- management strategies. This chapter reviews the efficacy and safety of strategies for weight loss, as well as the combinations of strategies that appear to be associated with successful loss. In addition, the elements of successful weight maintenance also will be reviewed since the difficulty in maintaining weight loss may contribute to the overweight problem. A brief discussion of public policy measures that may help prevent overweight and assist those who are trying to lose weight or maintain weight loss is also included. PHYSICAL ACTIVITY Increased physical activity is an essential component of a comprehensive weight-reduction strategy for overweight adults who are otherwise healthy. One of the best predictors of success in the long-term management of overweight and obesity is the ability to develop and sustain an exercise program (Jakicic et al., 1995, 1999; Klem et al., 1997; McGuire et al., 1998, 1999; Schoeller et al., 1997~. The availability of exercise facilities at military bases can reinforce exercise and fitness programs that are necessary to meet the services' physical readiness needs generally, and for weight management specifically. For a given individual, the intensity, duration, frequency, and type of physical activity will depend on existing medical conditions, degree of previous activity, physical limitations, and individual preferences. Referral for additional professional evaluation may be appropriate, especially for individuals with more than one of the above extenuating factors. The benefits of physical activity (see Table 4-1)
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES 81 are significant and occur even in the absence of weight loss (Blair, 1993; Kesaniemi et al., 2001~. It has been shown that one of the benefits, an increase in high-density lipoproteins, can be achieved with a threshold level of aerobic exercise of 10 to 1 1 hours per month. For previously sedentary individuals, a slow progression in physical activity has been recommended so that 30 minutes of exercise daily is achieved after several weeks of gradual build-up. This may also apply to some military personnel, especially new recruits or reservists recalled to active duty who may be entering service Mom previously very sedentary lifestyles. The activity goal has been expressed as an increase in energy expenditure of 1,000 kcal/wk (Jakicic et al., 1999; Pate et al., 1995), although this quantity may be insufficient to prevent weight regain. For that purpose, a weekly goal of 2,000 to 3,000 kcal of added activity may be necessary (Klem et al., 1997; Schoeller et al., 1997~. Thus, mental preparation for the amount of activity necessary to maintain weight loss must begin while losing weight (Brownell, 1999~. For many individuals, changing activity levels is perceived as more un- pleasant than changing dietary habits. Breaking up a 30-m~nute daily exercise "prescription" into 1 O-minute bouts has been shown to increase compliance over that of longer bouts (Jakicic et al., 1995, Pate et al., 1995~. However, over an 18- month period, individuals who performed short bouts of physical activity did not experience improvements in long-term weight loss, cardiorespiratory fitness, or physical activity participation in comparison with those who performed longer bouts of exercise. Some evidence suggests that home exercise equipment (e.g., a treadmill) increases the likelihood of regular exercise and is associated with greater long-term weight loss (Jakicic et al., 1999~. In addition, individual preferences are paramount considerations in choices of activity. When strength training or resistance exercise is combined with aerobic activity, long-term results may be better than those with aerobics alone (Poirier and Despres, 2001; Sothern et al., 1999~. Because strength training tends to build muscle, loss of lean body mass may be minimized and the relative loss of body fat may be increased. An added benefit is the attenuation of the decrease in resting metabolic rate associated with weight loss, possibly as a consequence of preserving or enhancing lean body mass. As valuable as exercise is, the existing research literature on overweight individuals indicates that exercise programs alone do not produce significant weight loss in the populations studied. It should be emphasized, however, that a large number of such studies have been conducted with middle-aged Caucasian women leading sedentary lifestyles. The failure of exercise alone to produce significant weight loss may be because the neurochemical mechanisms that regulate eating behavior cause individuals to compensate for the calories expended in exercise by increasing food (calorie) intake. While exercise pro- grams can result in an average weight loss of 2 to 3 kg in the short-term (Blair, 1993; Pavlou et al., 1989a; Skender et al., 1996, Wadden and Sarwer, 1999),
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82 WEIGHT AL4NAGEMENT outcome improves significantly when physical activity is combined with dietary intervention. For example, when physical activity was combined with a reduced- calorie diet and lifestyle change, a weight loss of 7.2 kg was achieved after 6 months to 3 years of follow-up (Blair, 1993~. Physical activity plus diet produces better results than either diet or physical activity alone (Blair, 1993; Dyer, 1994; Pavlou et al., 1989a, 1989b; Perri et al., 1993~. In addition, weight regain is significantly less likely when physical activity is combined with any other weight-reduction regimen (Blair, 1993; Klem et al., 1997~. Continued follow-up after weight loss is associated with improved outcome if the activity plan is monitored and modified as part of this follow-up (Kayman et al., 1990~. While studies have shown that military recruits were able to lose significant amounts of weight during initial entry training through exercise alone, the restricted time available to consume meals during Gaining probably contributed to this weight loss (Lee et al., 1994~. BEHAVIOR AND LIFESTYLE MODIFICATION The use of behavior and lifestyle modification in weight management is based on a body of evidence that people become or remain overweight as the result of modifiable habits or behaviors (see Chapter 3), and that by changing those behaviors, weight can be lost and the loss can be maintained. The primary goals of behavioral strategies for weight control are to increase physical activity and to reduce caloric intake by altering eating habits (Brownell and Kramer, 1994; Wilson, 1995~. A subcategory of behavior modification, environmental management, is discussed in the next section. Behavioral treatment, which was introduced in the 1960s, may be provided to a single individual or to groups of clients. Typically, individuals participate in 12 to 20 weekly sessions that last *om 1 to 2 hours each (Brownell and Kramer, 1994), with a goal of weight loss in the range of 1 to 2 lb/wk (Brownell and Kramer, 1994~. In the past, behavioral approaches were applied as stand-alone treatments to simply modify eating habits and reduce caloric intake. However, more recently, these treatments have been used in combination with low-calorie diets, medical nutrition therapy, nutrition education, exercise programs, monitoring, pharmacological agents, and social support to promote weight loss, and as a component of maintenance programs. Self-Monitoring and Feedback Self-monitoring of dietary intake and physical activity, which enables the individual to develop a sense of accountability, is one of the cornerstones of behavioral treatment. Patients are asked to keep a daily food diary in which they record what and how much they have eaten, when and where the food was consumed, and the context in which the food was consumed (e.g., what else they
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES 83 were doing at the time, what they were feeling, and who else was there). Additionally, patients may be asked to keep a record of their daily physical activities. Self-monitoring of food intake is open associated with a relatively immediate reduction in food intake and consequent weight loss (Blundell, 2000; Goris et al., 2000~. This reduction in food intake is believed to result from increased awareness of food intake and/or concern about what the dietitian or nutrition therapist will think about the patient's eating behavior. The information obtained from the food diaries also is used to identify personal and environ- mental factors that contribute to overeating and to select and implement appropriate weight-loss strategies for the individual (Wilson, 1995~. The same may be true of physical activity monitoring, although little research has been conducted in this area. Self-monitoring also provides a way for therapists and patients to evaluate which techniques are working and how changes in eating behavior or activity are contributing to weight loss. Recent work has suggested that regular self-monitoring of body weight is a useful adjunct to behavior modification programs (Jeffery and French, 1999~. Other Behavioral Techniques Some additional techniques included in behavioral treatment programs include eating only regularly scheduled meals; doing nothing else while eating; consuming meals only in one place (usually the dining room) and leaving the table after eating; shopping only from a list; and shopping on a full stomach (Brownell and Kramer, 1994~. Reinforcement techniques are also an integral part of the behavioral treat- ment of overweight and obesity. For example, subjects may select a positively reinforcing event, such as participating in a particularly enjoyable activity or purchasing a special item when a goal is met (Brownell and Kramer, 1994~. Another important component of behavioral treatment programs may be cognitive restructuring of erroneous or dysfunctional beliefs about weight regulation (Wing, 19981. Techniques developed by cognitive behavior therapists can be used to help the individual identify specific triggers for overeating, deal with negative attitudes towards obesity in society, and realize that a minor dietary infraction does not mean failure. Nutrition education and social support, discussed later in this chapter, are also components of behavioral programs. Behavioral treatments of obesity are frequently successful in the short-term. However, the long-term effectiveness of these treatments is more controversial, with data suggesting that many individuals return to their initial body weight within 3 to 5 years after treatment has ended (Brownell and Kramer, 1994; Klem et al., 19971. Techniques for improving the long-term benefits of behavioral treatments include: (l) developing criteria to match patients to treatments, (2) increasing initial weight loss, (3) increasing the length of treatment, (4) empha-
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84 WEIGHT AL4NAGEMENT sizing the role of exercise, and (5) combining behavioral programs with other treatments such as pharmacotherapy, surgery, or stringent diets (Brownell and Kramer, 1994~. Recent studies of individuals who have achieved success at long-term weight loss may offer other insights into ways to improve behavioral treatment strategies. In their analysis of data Tom the National Weight Control Registry, Klem and coworkers (1997) found that weight loss achieved through exercise, sensible dieting, reduced fat consumption, and individual behavior changes could be maintained for long periods of time. However, this population was self- selected so it does not represent the experience of the average person in a civil- ian population. Because they have achieved and maintained a significant amount of weight loss (at least 30 lb for 2 or more years), there is reason to believe that the population enrolled in the Registry may be especially disciplined. As such, the experience of people in the Registry may provide insight into the military population, although evidence to assert this win authority is lacking. In any case, the majority of participants in the Registry report they have made signifi- cant permanent changes in their behavior, including portion control, low-fat food selection, 60 or more minutes of daily exercise, self-monitoring, and well- honed problem-solving skills. Eating Environments A significant part of weight loss and management may involve restructuring the environment that promotes overeating and underactivity. The environment includes the home, the workplace, and the community (e.g., places of worship, eating places, stores, movie theaters). Environmental factors include the avail- ability of foods such as fruits, vegetables, nonfat dairy products, and other foods: of low energy density and high nutritional value. Environmental restructuring- empha-sizes frequenting dining facilities that produce appealing foods of lower energy density and providing ample time for eating a wholesome meal rather than grabbing a candy bar or bag of chips and a soda from a vending machine. Busy lifestyles and hectic work schedules create eating habits that may contribute to a less than desirable eating environment, but simple changes can help to counter-act these habits. Commanders of military bases should examine their facilities to identify and eliminate conditions that encourage one or more of the eating habits that promote overweight. Some nonmilitary employers have increased healthy eating options at worksite dining facilities and vending machines. Although multiple publications suggest that worksite weight-loss programs are not very effective in reducing body weight (Cohen et al., 1987; Forster et al., 1988; Frankle et al., l 986; Kneip et al., 1985; Loper and Barrows, 1985), this may not be the case for the military due to the greater controls the military has over its "employees" than do nonmilitary employers.
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NEIGH T-LOSS AND MAINTENANCE STRA TEGIES 85 Eating habits that may promote overweight: 1. Eating few or no meals at home 2. Opting for high-fat, calorie-dense foods 3. Opting for high-fat snack foods from strategically placed vending ma- chines or snack shops combined with allowing insufficient time to pre- pare affordable, healthier alternatives. 4. Consuming meals at sit-down restaurants that feature excessive portion sizes or"all-you-can-eat" buffets Simple changes that can modify the eating environment: 1. Prepare meals at home and can y bag lunches Learn to estimate or measure portion sizes in restaurants Learn to recognize fat content of menu items and dishes on buffet tables 4. Eliminate smoking and reduce alcohol consumption Substitute low-calorie for high-calorie foods 6. Modify the route to work to avoid a favorite food shop Physical Activity Environment Major obstacles to exercise, even in highly motivated people, include the time it takes to complete the task and the inaccessibility of facilities or safe places to exercise. Environmental interventions emphasize the many ways that physical activity can be fit into a busy lifestyle and seek to make use of what- ever opportunities are available (HHS, 1996~. Environmental changes may be needed to encourage female participation in exercise programs, such as accom- modation of the need for more after-exercise "repair time" by women and work- site facilities that are more "user friendly," such as measured indoor walking routes and lunchtime low-level aerobics classes (Wasserman et al., 20001. The availability of safe sidewalks and parks and alternative methods of transporta- tion to work, such as walking or bicycling, also enhance the physical activity environment. Establishing "car-free" zones is an example of an environmental change that could promote increased physical activity. Nutrition Education Management of overweight and obesity requires the active participation of the individual. Nutrition professionals can provide individuals with a base of information that allows them to make knowledgeable food choices.
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86 WEIGHT MANAGEMENT Nutrition education is distinct from nutrition counseling, although the con- tents overlap considerably. Nutrition counseling and dietary management tend to focus more directly on the motivational, emotional, and psychological issues . . . . , . . . . ~ · ~ . 1 ~ ~ ~ be. ~ _ _ ~_~ ~~~ 1 ~ OaaQ~l~LG~ WlLll ally ~Ull~llL ~~ w~ ~~—~~AA~ A~— ~~ ~~ .,_ . In addresses the how of behavioral changes in the dietary arena. Nutrition education on the other hand, provides basic information about the scientific foundation of nutrition that enables people to make infonned decisions about food, cooking methods, eating out, and estimating portion sizes. Nutrition education programs also may provide information on the role of nutrition in health promotion and disease prevention, sports nutrition, and nutrition for pregnant and lactating women. Effective nutrition education imparts nutrition knowledge and its use in healthy living. For example, it explains the concept of energy balance in weight management in an accessible, practical way that has meaning to the individual's lifestyle, including that in the military setting. Written materials prepared by various government agencies or by nonprofit health organizations can be used effectively to provide nutrition education. However, written materials are most effective when used to reinforce informal classroom or counseling sessions and to provide specific information, such as a table of the calorie content of foods. The format of education programs varies considerably, and can include formal classes, informal group meetings, or teleconferencing. A common background among group members is helpful (but seldom possible). ~^A~;~+~ ,;+h The ^..~^t tack Of ~~rPiabt lr~cc ~nr1 Vomit m~nnu~ment Educational formats that provide practical and relevant nutrition informa- tion for program participants are the most successful. For example, some mili- tary weight-management programs include field trips to post exchanges, restau- rants (fast-food and others), movies, and other places where food is purchased or consumed (Vorachek, 1999~. The involvement of spouses and other family members in an education pro- gram increases the likelihood that other members of the household will make permanent changes, which in turn enhances the likelihood that the program par- ticipants will continue to lose weight or maintain weight loss (Hart et al., 1990; Hertzler and Schulman, 1983; Sperry, 1985~. Particular attention must tee di- rected to involvement of those in the household who are most likely to shop for and prepare food. Unless the program participant lives alone, nutrition manage- ment is rarely effective without the involvement of family members. DIET Weight-management programs may be divided into two phases: weight loss and weight maintenance. While exercise may be the most important element of a weight-maintenance program, it is clear that dietary restriction is the critical component of a weight-loss program that influences the rate of weight loss.
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 87 Activity accounts for only about 15 to 30 percent of daily energy expenditure, but food intake accounts for 100 percent of energy intake. Thus, the energy bal- ance equation may be affected most significantly by reducing energy intake. The number of diets that have been proposed is almost innumerable, but whatever the. name, all diets consist of reductions of some proportions of protein, carbo- hydrate (CHO) and fat. The following sections examine a number of arrange- ments of the proportions of these three energy-containing macronutrients. Nutritionally Balanced, Hypocaloric Diets A nutritionally balanced, hypocaloric diet has been the recommendation of most dietitians who are counseling patients who wish to lose weight. This type of diet is composed of the types of foods a patient usually eats, but in lower quantities. There are a number of reasons such diets are appealing, but the main reason is that the recommendation is simple—individuals need only to follow the U.S. Department of Agriculture's Food Guide Pyramid. The Pyramid recommends that individuals eat a variety of foods, with the majority being grain products (e.g., bread, pasta, cereal, rice), eat at least five servings per day of fruits and vegetables; eat only moderate amounts of dairy and meat products; and limit the consumption of foods that are high in fat or sugar or contain few nutrients. In using the Pyramid, however, it is important to emphasize the portion sizes used to establish the recommended number of servings. For example, a majority of consumers do not realize that a portion of bread is a single slice or that a portion of meat is only 3 oz. A diet based on the Pyramid is easily adapted from the foods served in group settings, including military bases, since all that is required is to eat smaller portions. Even with smaller portions, it is not difficult to obtain adequate quantities of the other essential nutrients. Many of the studies published in the medical literature are based on a balanced hypocaloric diet with a reduction of energy intake by 500 to 1,000 kcal Mom the patient's usual caloric intake. The U.S. Food and Drug Administration (FDA) recommends such diets as the "standard treatment" for clinical trials of new weight-loss drugs, to be used by both the active agent group and the placebo group (FDA, 19961. Meal Replacement Meal replacement programs are commercially available to consumers for a reasonably low cost. The meal replacement industry suggests replacing one or two of the three daily meals with their products, while the third meal should be sensibly balanced. In addition, two snacks consisting of fruits, vegetables, or diet snack bars are recommended each day. Using this plan, individuals con- sume approximately 1,200 to 1,500 kcal/day.
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88 WEIGHT MANAGEMENT A number of studies have evaluated long-term weight maintenance using meal replacement, either self-managed (Flechtner-Mors et al., 2000; Heber et al., 1994; Rothacker, 2000), with active dietary counseling, or with behavior modification programs (Ashley et al., 2001; Ditschuneit and Flechtner-Mors, 2001; Ditschuneit et al., 1999) compared with traditional calorie-restricted diet plans. The largest amount of weight loss occurred early in the studies (about the first 3 months of the plan) (Ditschuneit et al., 1999; Heber et al., 1994~. One study found that women lost more weight between the third and sixth months of the plan, but men lost most of their weight by the third month (Heber et al., 1994~. All of the studies resulted in maintenance of significant weight loss after 2 to 5 years of follow-up. Hill's (2000) review of Rothacker (2000) pointed out that the group receiving meal replacements maintained a small, yet significant, weight loss over the 5-year program, whereas the control group gained a signifi- cant amount of weight. Active intervention, which included dietary counseling and behavior modification, was more effective in weight maintenance when meal replacements were part of the diet (Ashley et al., 2001~. Meal replacements were also found to improve food patterns, including nutrient distribution, intake of micronutrients, and maintenance of fruit and vegetable intake. Long-term maintenance of weight loss with meal replacements improves biomarkers of disease risk, including improvements in levels of blood glucose (Ditschuneit and Fletchner-Mors, 2001), insulin, and triacylglycerol; improved systolic blood pressure (Ditschuneit and Fletchner-Mors, 2001; Ditschuneit et al., 19994; and reductions in plasma cholesterol (Heber et al., 1994~. Winick and coworkers (2002) evaluated employees in high-stress jobs (e.g., police, firefighters, and hospital and aviation personnel) who participated in worksite weight-reduction and maintenance programs that used meal replace- ments. The meal replacements were found to be effective in reducing weight and maintaining weight loss at a 1-year follow-up. In contrast, Bendixen and co- workers (2002) reported from Denmark that meal replacements were associated with negative outcomes on weight loss and weight maintenance. However, this was not an intervention study; participants were followed for 6 years by phone interview and data were self-reported. Unbalanced, Hypocaloric Diets Unbalanced, hypocaloric diets restrict one or more of the calorie-containing macronutrients (protein, fat, and CHO). The rationale given for these diets by their advocates is that the restriction of one particular macronutrient facilitates weight loss, while restriction of the others does not. Many of these diets are published in books aimed at the lay public and are often not written by health professionals and often are not based on sound scientific nutrition principles. For some of the dietary regimens of this type, there are few or no research publications and virtually none have been studied long term. Therefore, few
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 89 conclusions can be drawn about the safety, and even about the efficacy, of such diets. The major types of unbalanced, hypocaloric diets are discussed below. High-Protein, Low-Carbohydrate Diets There has been considerable debate on the optimal ratio of macronutrient intake for adults. This research usually compares the amount of fat and CHO; however, there has been increasing interest in the role of protein in the diet (Hu et al., 1999; Wolfe and Giovannetti, 1991~. Studies have looked for the effects of a higher protein diet (CHO/prote~n ratio ~1.0) compared with a higher CHO diet (CHO/protein ratio ~3.0~. Although the high-protein diet does not produce significantly different weight loss compared with the high-CHO diet (Layman et al., 2003a, 2003b; Piatti et al., 1994), the high-protein diet has been reported to stimulate greater improvements in body composition by sparing lean body mass (Layman et al., 2003a; Piatti et al., 1994~. High-protein, low-CHO diets were introduced to the American public during the 1970s and 1980s by Stillman and Baker (1978) and by Atkins (Atkins, 1988; Atkins and Linde, 1978), and more recently, by Sears and Lawren (1998~. Some of these diets are high in fat (> 35 percent of kcal), while others have moderate levels of fat (25-35 percent of kcal). While most of these diets have been promoted by nonscientists who have done little or no serious scientific research, some of the regimens have been subjected to rigorous studies (Skov et al., 1999a, l999b). There remains, however, a lack of randomized clinical trials of 2 or more years' duration, which are needed to evaluate the potent beneficial effect of weight loss (accomplished using virtually any dietary regimen, no matter how unbalanced) on blood lipids. In addition, longer studies are needed to separate the beneficial effects of weight loss from the long-term effects of consuming an unbalanced diet. Authors of books aimed at the lay public have proposed advantages of high protein diets, including that eating a high-protein, low-CHO diet produces a "near-euphoric" state of maximal physical and mental performance (Sears and Lawren, 1998~. These claims are unsupported by scientific data. Although these diets are prescribed to be eaten ad libitum, total daily energy intake tends to be reduced as a result of the monotony of the food choices, other prescripts of the diet, and an increased satiety effect of protein. In addition, the restriction of CHO intake leads to the loss of glycogen and marked diuresis (Coulston and Rock, 1994; Miller and Lindeman, 1997; Pi-Sunyer, 19884. Thus, the relatively rapid initial weight loss that occurs on these diets predominantly reflects the loss of body water rather than stored fat. This can be a significant concern for military personnel, where even mild dehydration can have detri- mental effects on physical and cognitive performance. For example, small changes in hydration status can affect a military pilot's ability to sense changes . .... . In equlllorlum.
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102 WEIGHT MANAGEMENT available data suggest that combination therapy is somewhat more effective than therapy with single agents. Combinations such as phentermine and fenfluramine or ephedrine and caffeine produce weight losses of about 15 percent or more of initial body weight compared with about 10 percent or less with single drug use. However, due to reported side-effects of cardiac valve lesions and pulmonary hypertension, fenfluramine and dextenfluramine are no longer available. Results of tests using combinations of phentermine with selective serotonin reuptake inhibitors (mainly fluoxetine or sertraline) have been reported in ab- stracts or preliminary reports (Dhuran&ar and Atkinson, 1996; Griffen and An- chors, 1998~. These combinations produced weight losses somewhat less than that of the combination treatment of ephedrine-caffeine, but greater than that of treatment with single agents (Dhurandhar and Atkinson, 1996~. Safer. Anchors (1997) used the combination of phentermine and fluoxetine in a large series of patients and suggested that this combination is safe and effec- tive. Griffen and Anchors (1998) reported that the combination of phentermine- fluoxetine was not associated with the cardiac valve lesions that were reported for fenfluramine and dexfenfluramine. Alternative Medicines, Herbs, and Diet Supplements In 1994, Congress passed the Dietary Supplement Health and Education Act, which exempted dietary supplements (including those promoted for weight loss) from the requirement to demonstrate safety and efficacy. As a result, the variety of over-the-counter preparations touted to promote weight loss has ex- ploded. Dietary supplements include compounds such as herbal preparations (often of unknown composition), chemicals (e.g., hydroxycitrate, chromium), vitamin preparations, and protein powder preparations. With the exception of herbal preparations of ephedrine and caffeine, none of these compounds have produced more than a minimal weight loss and most are ineffective or have been insufficiently studied to determine their efficacy. Furthermore, while little is known about the safety of many of these compounds, there are a growing num- ber of adverse event reports for several of them. Table 4-4 summarizes the cur- rent safety and efficacy profile of a number of alternative compounds promoted for the purpose of weight loss. The combination of ephedrine and caffeine to treat obesity has been re- ported to produce weight losses of 15 percent or more of initial body weight (Daly et al., 1993; Toubro et al., 1993~. Both drugs are the active ingredients in a number of herbal weight-loss preparations. Weight loss is maximal at about 4 to 6 months on this combination, but body-fat levels may continue to decrease through 9 to 12 months, with increases in lean body mass (Toubro et al., 1993~. This observation suggests that the combination may be a beta-3 adrenergic ago- nist (Liu et al., 1995; Toubro et al., 19939.
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES 103 Reports of cardiovascular and cerebrovascular events following use of ephedrine and caffeine to treat obesity have reached sufficient frequency that FDA and the Federal Trade Commission have begun to investigate the safety of this combination and have issued warnings to consumers. In addition, FDA has proposed new regulations for the labeling of products containing ephedrine, which would require warning statements for potential adverse health effects. Use of ephedrine alone or in combination with caffeine has been associated with a wide range of cardiovascular, cerebrovascular, neurological, psychological, gastrointestinal, and other symptoms in adverse events reports (Hailer and Be- nowitz, 2000; Shekelle et al., 2003~. Some prospective studies do not support the concept that there are major adverse events with ephedrine and caffeine (Boozer et al., 2001, 2002; Greenway, 2001; Kalman et al., 2002), but these studies were conducted using healthy individuals selected using careful exclusion criteria. FUTURE DRUGS FOR THE TREATMENT OF OBESITY Body weight, body fat, energy metabolism, and fat oxidation are regulated by numerous hormones, peptides, neurotransmitters, and other substances in the body. Drug companies are devoting a large amount of resources to find new agents to treat obesity. Potential candidates include cholecystokinin, cortioco- tropin-releasing hormone, glucagon-like peptide 1, growth hormone and other growth factors, enterostatin, neurotensin, vasopressin, anorectin, ciliary neuro- trophic factor, and bombesin, all of which potentially either inhibit food intake or reduce body weight in humans or animals (Bray, 1992b, 1998; Ettinger et al., 2003; Okada et al., 1991; Rudman et al., 1990; Smith and Gibbs, 1984~. Neuropeptide Y and galanin are central nervous system neurotransmitters that stimulate food intake (Bray, 1998; Leibowitz, 1995), so antagonists to these substances might be expected to reduce food intake. Beta-3 adrenergic receptor agonists reduce body fat and increase lean body mass in animals (Stock, 1996; Yen, 1995), but human analogs have not been identified that are effective and safe in humans. Several types of uncoupling proteins have been identified as being involved with the regulation of energy metabolism and body fat (Bao et al., 1998; Bouchard et al., 1998; Chagnon et al., 2000; Perusse et al., 1999), but no agents based on these proteins have yet been produced to treat obesity. As discussed in Chapter 3, seven single gene defects have been reported to produce obesity in humans (Perusse et al., 1999~. The leptin gene is defective in ob/ob mice, and leptin administration has been shown to be highly effective in reducing body weight in these mice (Campfield et al., 1995; Halaas et al., 1995; Pelleymounter et al., 19953. A very small number of humans with this gene de- fect have been identified, and at least one responded to leptin (Clement et al., 1998; Perusse et al., 19991. Leptin levels are high in most obese individuals (Considine et al., 1996; Phillips, 1998), and preliminary trials of administration of leptin to these individuals show modest effects. Defects in the genes for
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104 WEIGHT MANAGEMENT TABLE 4-4 Alternative Medicines, Herbs, and Supplements Used for Weight Loss Name/Compound Description Bladderwrack Chitosan Chromium CLA DHEA Ephedrine fat-burning stack Garcinia cambogia Germander HMB Olestra (Lawson et al., 1997) Plantago Pyruvate Sunflower St. John's Wort SOURCE: Allison et al. (2001~. Fucus vesiculosus Polymer of glucosamine derived from chitin Cr—an essential element Conjugated linoleic acid Dehydroepiar~drosterone Ephedrine with caffeine and aspirin, ma huang with guarana and willow bark Contains hydroxycitrate (HCA) Teucrium chamaedrys ,B-Hydroxy-p-methylbutryrate Mixture of hexa-, hepta-, and octa-esters of sucrose formed from long-chain fatty acids isolated from edible oils Plantain leaf or psyllium seed A 3-carbon compound Heliallthus annuus Hypericum perforatum protein convertase subtilisin/kexin type 1, PPAR-gamma, and pro-opiomelano- cortin and in the genes for the receptors for leptin, thyroid hormone, and melanocortin-4R (Bouchard et al., 1998; Chagnon et al., 2000; Perusse et al., 1999) have been identified in humans. It may be possible in the future to develop gene therapy or products that correct these defects in order to treat obesity. Summary Although obesity drugs have been available for more than 50 years, the concept of long-term treatment of obesity with drugs has been seriously advanced only in the last 10 years. The evidence that obesity, as opposed to overweight, is a pathophysiological process of multiple etiologies and not simply a problem of self-discipline is gradually being recognized~besity is
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 105 Safety Efficacy for Weight/Fat Loss No, increases risk of hyperthyroidism Insufficient data Yes, when used in recommended doses Yes, preliminary report No Adverse effects have been reported (Hailer and Benowitz, 2000; HHS/FDA, 1997; Shekelle et al., 2003) Insufficient data No Yes, short-term Yes Unknown, may cause gastrointestinal distress and affect absorption of medications Insufficient data Yes Insufficient data Insufficient data No (Pittler et al., 1999; Wuolijoki et al., 1999) Likely ineffective (Hallmark et al., 1996; Lukaski et al., 1996; Trent and Thieding- Cencel, 1995) Yes, preliminary report (Blankson et al., 2000) Yes, but studies are limited Yes, appropriate dose arid in combination with caffeine (Astrup et al., 1992a, 1992b; Boozer et al., 2001) Insufficient data, possibly ineffective at dose of 1,500 mg/d in obese adults (Heymsfield et al., 1998) Insufficient data Yes Insufficient data Insufficient data No Insufficient data Insufficient data similar to other chronic diseases associated with alterations in the biochemistry of the body. Most other chronic diseases are treated with drugs, and it is likely that the primary treatment for obesity in the fixture will be the long-term administration of drugs. Unfortunately, current drug treatment of obesity produces only moderately better success than does diet, exercise, and behavioral modification over the intermediate term. Newer drugs need to be developed, and combinations of current drugs need to be tested for short- and long-term effectiveness and safety. As drugs are proven to be safe and effective' their use in less severe obesity and overweight may be justified. The appropriateness of using weight-loss drugs in the military population requires careful consideration. On average, a 5 to 10 percent weight loss can improve comorbid conditions associated with obesity, but it is not known if this degree of weight reduction by itself would improve fitness or if it could be expected to improve performance in all military contexts. The side effects that
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106 WEIGHT MANAGEMENT are sometimes encountered might also restrict the use of weight-loss drugs in some military contexts. On the other hand, the military is losing or is in danger of losing otherwise qualified individuals who cannot "make weight." Such people might be able to keep their weight within regulation if they are allowed to take weight-loss drugs for the remainder of their term in the military. The frequency of known side effects of current weight-loss drugs is sufficiently low that the potential for adverse events would not seem to be a reason to avoid the use of these drugs by military personnel. The use of available dietary supplements and herbal preparations to control body weight is generally not recommended because of a lack of demonstrated efficacy of such preparations, the absence of control on their purity, and evi- dence that at least some of these agents have significant side effects and safety problems. The occurrence of potential adverse effects (e.g., dehydration, mood alterations) would be of particular concern for military personnel. SURGERY Although it would be expected that very few active duty military personnel would qualify for consideration for obesity surgery, a review of weight- management programs would not be complete without a discussion of this option. For massively obese individuals (those with a BMI above 35 or 40), the modest weight losses from behavioral treatments and/or drugs do not alter their obese status. For these individuals, obesity surgery may produce massive, long- term weight loss. Recent studies have shown dramatic improvements in the morbidity and mortality of those who are massively obese, and surgery is being recommended with increasing frequency for these individuals (Hubbard and Hall, 1991~. Table 4-5 presents the rationale and results of all forms of obesity surgery. Individuals who are candidates for obesity surgery are those who (1) exhibit any of the complications of obesity such as diabetes, hypertension, dyslipidemia, sleep disorders, pulmonary dysfunction, or increased intracranial pressure and have a BMI above 35, or (2) have a BMI above 40. Gastric bypass is currently the most commonly used procedure for obesity surgery. Following this procedure, patients lose about 62 to 70 percent of excess weight and maintain this loss for more than 5 years (Kral, 1998; MacDonald et al., 1997; Pories et al., 1992, 1995; Sugerman et al., 1989~. Biliopancreatic bypass, another type of obesity surgery, and its variations produce weight losses comparable or superior to gastric bypass (Kral, 1998~. In addition to massive weight loss, individuals who undergo obesity surgery experience improvements in health status relative to hypertension, dyslipidemia, sleep apnea, pulmonary function (oxygen saturation and oxyhemoglobin levels and decreased carbon dioxide saturation) (Sugerman, 1987; Sugerman et al., 1986, 1988), obesity-
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 107 hypoventilation syndrome, and pseudotumor cerebri, urinary incontinence, and pulmonary dysfunction possibly due to increased intra-abdominal pressure (Sugerman et al., 1995, 19991. Obesity surgery is, however, considered the treatment of last resort because of the short- and long-term complications associated with the surgery. Pe- rioperative mortality is small but significant (about 0.3 to 2 percent) and appears to vary inversely with the experience of the surgeon (Kral, 1998~. Other poten- tial side effects include vomiting, diarrhea, electrolyte abnormalities, liver fail- ure, renal stones, pseudo-obstruction syndrome, arthritis syndrome, and bacterial overgrowth syndromes. THE USE OF STRUCTURED MAINTENANCE PROGRA1\/IS When to Use a Maintenance Program The long-term success of weight management appears to depend on the in- dividual participating in a specific and deliberate follow-up program. Programs to aid personnel in weight maintenance or prevention of weight gain are appropriate when: . An individual has successfully achieved his or her weight-loss goal and now seeks to maintain the new weight, . An individual who is gaining weight has taken a weight-loss readiness assessment and has determined that he or she is not ready for weight loss at this time, or An overweight individual is temporarily excluded from a weight- reduction program until a medical, physical, or psychological problem stabilizes. Components of a Maintenance Program A comprehensive weight-maintenance strategy has five fundamental com- ponents: 1. It helps the patient select a weight range within which he or she can re- alistically stay and, if possible, minimize health risks. 2. It provides an opportunity for continued monitoring of weight, food in- take, and physical activity. 3. It helps the patient understand and implement the principle of balancing the energy consumed from food with routine physical activity. 4. It helps the patient establish and maintain lifestyle change strategies for a sufficiently long period of time to make the new behaviors into permanent habits (a minimum of 6 months has been suggested [Wing, 199811. 5. It considers the long-term use of drugs.
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108 HEIGHT MANAGEMENT TABLE 4-5 Surgical Procedures Used for Treatment of Obesity in Humans Procedure Intestinal resection (Kral, 1989) Proposed Mechanism Small intestine malabsorption Intestinal bypass (Kral, 1998) Jujuno-ileal bypass (Hallberg et al., 1975; Kral, 1998; Payne and DeWind, 1969) End-to-end, end-to-side (Bray et al., 1977) Biblio-pancreatic bypass (Kral, 1998; Scopinaro et al., 1979, 1998) Stomach to ileum (Kral, 1998) Gastric stapling (MacLean et al., 1993) Gastric bypass (Benotti et al., 1989; Linner, 1982; Yale, 1989) Vertical banded gastroplasty (Benotti et al., 1989; Linner, 1982; Mason, 1982, Yale, 1989) Gastric wrapping (Kral, 1998) . . Jaw wiring Subdiaphragmatic truncal vagotomy ~ pyloroplasty (Holle and Bauer, 1978) Liposuction (Kral 1998) , Small intestine malabsorption Small intestine malabsorption Small intestine malabsorption Partial gastric outlet obstruction, limited food intake Reduced food intake secondary to very small stomach size arid restricted flow rate into small intestine, reduced intestinal absorption Reduced food intake secondary to very small stomach size and restricted flow rate into small intestine, reduced intestinal absorption Reduced food intake secondary to very small stomach size and restricted flow rate into small intestine, reduced intestinal absorption Prevents solid food consumption Loss of motor function leads to stomach distension which causes a feeling of fullness that may signal the central nervous system Removal of subcutaneous fat " Humoral or neural effects of exposure of ileum to nutrients may lead to increased effects. Helping Patients Learn How to Balance Energy Individuals who have achieved a weight-loss goal generally fall into one of two groups: those who see no point in participating in a maintenance program since they believe they know how to keep the weight off and those who remain open to change and improving their skills in weight management. The critical role of the health care provider is to motivate the former group to learn the skills necessary for weight management. The skills necessary to:
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 109 Results Notes 80% Decrease in energy intake in immediate postoperative period Gradual weight increase over 2 years High failure rate 1 00% Failure Average weight loss ~ 20 kg Effects minimal Considered more effective than vertical banded gastroplasty and gastric wrapping, causes dumping, laparoscopic (leads to decrease in perioperative complications Rarely used due to large number of complications Procedure abandoned Cosmetic use only · Maintain regular exercise for at least 60 minJday or an expenditure of 2,000 to 3,000 kcal/wk (8,368 kJ) (Klem et al., 1997; Schoeller et al., 1997~. · Decrease the amount of energy-dense foods eaten (especially those that are low in nutrients). · Practice healthy eating by including fruits, vegetables, and whole grains in the diet. · Understand portion control. · Access the services of nutrition counselors or other forms of guidance.
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110 Helping Patients Establish Permanent Lifestyle Change Strategies HEIGHT MANAGEMENT As mentioned above, individuals who have lost weight need to make per- manent lifestyle changes in order to maintain their loss. To assist patients in making these changes, successful maintenance programs will include education on and assistance with the following factors (Foreyt and Goodrick, 1993, 1994; Kayman et al., 1990~: · Self-monitoring. Regular weighing and recording of daily food intake and physical activity for the first month or two of the maintenance period and during periods of increased exposure to food (e.g., during the holidays). If weight gain occurs, reinstitution of this practice may help bring weight back into control. Frequent follow-up contact with counselors is also crucial (Perri et al., 19931. Effective follow-up consists of a schedule of regular weekly to monthly contacts by mail, phone, or in person. Support groups may substitute for some of this follow-up with a health care provider, but should not replace it. Physical activity. Daily physical activity is key to successful weight maintenance; it is the factor cited as the most important in maintaining weight loss by the majority of individuals in the National Weight Loss Registry (Klem et al., 1997~. An average of 80 min/day of moderate activity or 35 min/day of vigorous activity is needed to maintain weight (Schoeller et al., 1997~. · Problem solving. Learning to identify and anticipate problems that threaten to undermine success is necessary. Problem solving skills allow the individual to craft strategies that will resolve problems as they emerge. · Stress management. Exercise, relaxation, and social support can help reduce stress. Techniques to reduce stress can be critical for some individuals who overeat in response to stress. . Relapse prevention. Relapse, temporary loss of control, and return to old behaviors is common. The key to relapse prevention is learning to anticipate high-risk situations and to devise plans to reduce the damages. Patients need to learn to forgive themselves for a lapse and view it as a "learning experience." Reestablishing control is crucial. . -= - Or ~ Social infZuence/support. Sabotage by family or friends is seen often and may be stressful for the individual who is trying to maintain weight. The skills to recognize intentional or unintentional sabotage may be learned. In ex- treme cases, a choice may need to be made between the weight-maintenance program or the relationship. Identifying a fresh circle of supporters or starting a support group may be useful. PUBLIC POLICY MEASURES To the extent that the epidemic of obesity can be attributed to changes in our living and working environments (the increased availability of calorie-dense
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES 111 foods and decreased opportunity to expend energy), public policy efforts may help prevent overweight and may assist those who are trying to lose weight or maintain weight loss (Koplan and Dietz, 19999. Some measures that have been suggested and/or tried include the following: · Increasing choices and decreasing prices of low-calorie (and low-fat) foods (e.g., fruits and vegetables) offered at worksite eating places and in vend- ing machines (French et al., 1997; Hoerr and Louden, 1993) · Instituting workplace and community programs that include regular monitoring, nutrition and health promotion, overweight prevention education, and exercise classes or groups · Renovating community spaces to provide more and safer spaces for physical activity · Modifying work environments or schedules to encourage greater phys cal activity on and off the job · Mandating regular physical activity during the workday (IOM, 1998~. SUMMARY ,1- Apart from the obvious need to increase energy expenditure relative to intake, none of the strategies that have been proposed to promote weight loss or maintenance of weight loss are universally recognized as having any utility in weight management. The efficacy of individual interventions is poor, and evidence regarding the efficacy of combinations of strategies is sparse, with results varying from one study to another and with the individual. Recent studies that have focused on identifying and studying individuals who have been successful at weight management have identified some common techniques. These include self-monitoring, contact with and support from others, regular physical activity, development of problem-solving skills (to deal with difficult environments and situations), and relapse-prevention/limitation skills. However, an additional factor identified among successful weight managers, and one not generally included in discussing weight-management techniques, is individual readiness that is strong personal motivation to succeed in weight management.
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an extremely sensitive area of research, the military could acicIress the question of whether genetic screening for obesity-prone indivicluals is appropriate for their mission. Role of Infectious Disease in Obesity A provocative hypothesis that has been proposer! as an explanation for at least some of the increase in the prevalence of obesity is that one or more viral infections may produce obesity. Several animal viruses produce obesity in animals, anti both animal and human viruses have been associated with obesity in humans (Dhuranc~har et al., 1997, 2000.~. Although the current committee was not constituted to evaluate this particular issue, it was presenter! at the committee's workshop and thus is mentioned here as an area where numerous research questions exist on the role of viruses in the etiology of obesity. Both basic and clinical studies are needed to identify whether human adenoviruses that have been demonstrated to produce obesity in animals are associated with obesity in humans. 6-~5
Representative terms from entire chapter: