Strategies for Changing Eating and Exercise Behavior

Transcription

1 650 PRESENT KNOWLEDGE IN NUTRITION/8th Edition Chapter 57 Rena R. Wing, Amy Gorin, and Deborah Tate Strategies for Changing Eating and Exercise Behavior The leading causes of disease and death in the United States coronary heart disease and cancer are related to lifestyle factors. Changing eating and exercise habits and eliminating smoking could markedly reduce the prevalence of these diseases. The goal of this chapter is to provide readers with an overview of behavioral strategies that can be used to modify lifestyle behaviors. Although the behavioral principles are applicable to changing any type of health habit, this chapter will focus primarily on obesity and will review strategies that may help in both treating and preventing this disease. History of Behavioral Weight Loss Programs The underlying premise of a behavioral approach is the functional analysis of behavior, also known as the A- B-C model. A functional analysis involves identifying the behaviors to be changed, which for obesity would be eating and exercise behaviors; the antecedent cues in the environment; and the consequences or reinforcers that influence the behaviors. Behaviorists propose that by changing the antecedents and consequences, it is possible to change the behavior: Antecedents Behavior Consequences. The earliest application of behavioral principles to the problem of obesity occurred in the 1960s 1970s. With the notable exception of Stuart s initial study of 8 overweight women (1), these early behavioral weight loss programs were typically conducted in groups with mildly overweight patients and lasted 10 weeks. The primary behavior targeted was a change in eating patterns (when and where food was eaten) rather than total energy intake. Similarly, participants were encouraged to change activity patterns by strategies such as using stairs instead of elevators, but no specific energy goals for physical activity were prescribed. These early studies produced weight losses of 3.8 kg over an 8 10-week treatment program and were shown to be more effective than alternative approaches such as nutrition education or psychotherapy. The next generation of behavioral programs, conducted in the 1980s, placed greater emphasis on energy intake and expenditure and typically prescribed moderate goals for these behaviors. Increased attention was also given to changing cognitions related to eating and exercise. With a more balanced focus on diet, exercise, and behavior (rather than focusing entirely on behavior), these programs produced average weight losses of 8.5 kg over 15 weeks. More recent weight loss programs have continued these trends (2). Treatments have been lengthened still further and now often involve weekly meetings for 26 weeks; a few studies have used weekly meetings for an entire year. The emphasis on nutrition has been further expanded and patients are often taught to monitor grams of fat as well as energy. Moreover, the energy intake goals are often stricter (some studies have even used very-lowcalorie diets [VLCDs]) and more structured exercise and higher exercise goals are sometimes included. Weight loss has averaged 9.7 kg over an average of 27 weeks (2). Typically, treatments are stopped after weeks and participants are contacted 1 year later to determine whether the weight loss has been maintained. On average, patients maintain a weight loss of 5.6 kg, or 60% of their initial weight loss. Few studies have included longer follow-up. It appears, however, that by 3 5-year follow-up, patients are back to their baseline weight (3). Behavioral Strategies This section provides a brief description of the key behavioral strategies used in weight loss programs. These same basic strategies would be applicable to changing any type of nutrition behavior. Identifying the behaviors to be changed. The first step of a behavioral intervention is to identify the specific behaviors to be modified. For example, for weight loss the key behaviors targeted are those related to energy balance

2 CHANGING EATING and EXERCISE BEHAVIOR/Wing, Gorin, and Tate 651 (energy consumed and expended). In applying behavioral principles to the reduction of cholesterol levels, the key behaviors would include reductions in saturated fat and cholesterol intake. In an intervention to reduce blood pressure, reducing sodium intake would be an additional behavioral focus. Setting goals. In changing behaviors, it is helpful to set specific goals that can be achieved by the participant. Often both behavioral goals and physiological (outcome) goals are identified. For example, participants in weight loss programs may aim to consume no more than 1200 kcal/ day (5023 kj/day) or to expend at least 1000 kcal/week (4184 kj/week) in exercise; a weight loss goal of 0.9 kg/week (2 lb/week) is often used. Short-term goals have been shown to be more effective than long-term goals in promoting behavior change (4). Behaviors are often shaped by setting easier goals initially and then increasing the goal as the participant progresses. An example of shaping is seen in physical activity, where participants are first helped to increase their activity to 250 or 500 kcal/week (1046 or 2092 kj/week) before attempting the 1000-kcal/week (4184-kJ/ week) goal. Self-monitoring. A key strategy in the behavioral treatment of obesity is teaching participants to observe and record their own eating- and activity-related behavior, a technique known as self-monitoring. A variety of information can be recorded through self-monitoring including the type and amount of food eaten, the number of calories in each food, the number of grams of fat, and other eatingrelated items such as eating situation and premeal mood. Similarly, types and amounts of physical activity can be recorded in minutes or calories. Participants are instructed to record their intake daily and bring their self-monitoring books to group meetings, providing an opportunity for feedback from group leaders and other participants. Selfmonitoring is usually done daily for the initial 6 months of treatment and then periodically during maintenance. Several studies support the utility of self-monitoring, suggesting a strong association between the completeness and consistency of self-monitoring and weight loss (5). Stimulus control. As mentioned earlier, a central tenet of behavior modification is that an individual s behavior is influenced by the environment. Thus, by manipulating their surroundings, participants can change the likelihood of behavioral outcomes. Participants in behavioral treatment programs are thus taught to restructure their environment to decrease cues for inappropriate food consumption and increase cues for appropriate diet and exercise (1). For example, participants are instructed to limit their purchases of high-fat foods and if they purchase these foods, to store them out of sight. Conversely, participants are encouraged to purchase more fruits and vegetables and increase the visibility of these items by storing them in prominent locations. Similarly, they are encouraged to put items related to exercise in places where they will be seen frequently. Other stimulus control strategies such as restricting eating to a designated place and eliminating the pairing of eating with other activities (e.g., watching television, reading) may also be effective for altering antecedents that influence eating behavior. Likewise, stimulus control techniques can be used to change other types of dietary behaviors; for example, individuals attempting to reduce their blood pressure might be instructed to remove the salt shakers from the table. Problem solving. When attempting to make permanent lifestyle changes, participants face many obstacles. To help participants successfully navigate this process, training in problem-solving skills is included in behavioral treatment programs. Participants are taught to 1) identify a specific problem that is hindering their weight loss effort, 2) generate as many solutions as possible to the problem, 3) evaluate the possible solutions and select one, 4) implement the solution, and 5) evaluate the outcome and repeat the problem-solving process if necessary. Problem-solving techniques are used for individually identified problems; for example, one participant may have difficulty with overeating while preparing dinner whereas another may focus on the difficulty of eating in restaurants. Cognitive restructuring. A more recent addition to behavioral weight loss treatment is cognitive restructuring. Cognitive restructuring involves identifying and modifying maladaptive thoughts contributing to overeating and physical inactivity. These thoughts can take several forms, such as dichotomous thinking (e.g., If I can t exercise for 30 minutes, I might as well not do it at all ) and rationalization (e.g., I ve had a stressful day, I deserve a piece of cake ). Participants are often unaware of the effect thoughts have on behavior. As part of cognitive restructuring, participants develop more positive self-statements to assist in behavior change. Relapse prevention. Helping participants prepare and plan for lapses or slips in the weight loss process is also included in behaviorally based programs. An extension of Marlatt and Gordon s (6) work with addictions, relapse prevention in behavioral weight-control programs involves teaching participants to anticipate problematic situations that might result in overeating and develop specific strategies for overcoming these lapses. Participants are encouraged to have a plan in place so that one overeating slip or lapse does not develop into a full-blown relapse. Changing Eating Behavior As noted above, the behaviors that must be targeted to produce weight loss are the behaviors related to energy balance. However, the best way to accomplish these changes and optimize long-term adherence remains unclear. Little information exists about very basic aspects of these behaviors, for example, the best level of energy intake to prescribe and the types of macronutrient composition of the diet to recommend. In the following sections, we will describe some of the behavioral research that has addressed these issues. Readers interested in more informa-

3 652 PRESENT KNOWLEDGE IN NUTRITION/8th Edition tion about behavior changes to reduce intake of saturated fat or sodium or to increase intake of fiber and fruits and vegetables are referred to the excellent review by Kumanyika et al. (7). Energy intake. Behavioral weight loss programs typically use low-calorie diets of kcal/day ( kj/day) designed to produce weight losses of kg/week (1 2 lb/week). However, several years ago there was a great deal of interest in the use of VLCDs during the initial phase of a behavioral program (8, 9). VLCDs provide kcal/day ( kj/day), typically given as liquid formula or lean meat, fish, and fowl. The advantage of these regimens is that they produce large initial weight losses, averaging 20 kg over 12 weeks. The thought was to combine VLCDs with behavioral strategies so that the VLCD would increase initial weight loss and the behavioral techniques would help maintain the weight loss long term. Wadden et al. (3, 9, 10) and Wing et al. (11, 12) conducted several trials comparing low-calorie diets with VLCDs used in combination with behavioral techniques. In all of these studies, the VLCDs were clearly effective in increasing initial weight loss. However, despite providing ongoing weekly contact with patients (10) and even using a second 12-week period of VLCD (12), the initial large weight losses produced by the VLCD were followed by large weight regains. Thus, by 1-year follow-up, there were no significant differences in weight loss for VLCD compared with low-calorie diet groups. Recently, Williams and colleagues (13) experimented with a different approach to using VLCDs. Patients followed a VLCD regimen for 1 day each week or 5 consecutive days every 5 weeks. These regimens improved weight losses through 20 weeks, but it remains unknown whether patients would continue intermittent use of VLCDs long term. Macronutrient composition. A second issue relates to the macronutrient composition of the diet. In the past, behavioral researchers focused primarily on total calories (energy intake) and paid less attention to the types of foods consumed. However, on the basis of epidemiological and metabolic studies showing an association between dietary fat intake and body weight (14), researchers began to examine whether restricting fat intake would improve longterm weight loss outcome. Jeffery and colleagues (15) compared the effect of restricting energy with restricting fat intake. They studied 122 women, half of whom were given a 20-g/day fat goal (and no restriction on energy) and the other half were given a kcal/day ( kJ/ day) goal (and no restriction on fat). No differences in weight loss between the 2 groups were observed at the end of the 6-month program or at 18-month follow-up. The combination of restricting energy and fat intake was examined by Schlundt et al. (16) (in comparison with a group that only restricted fat) and by Pascale et al. (17) (in comparison with a group that only restricted energy). In both studies there was some evidence that the combination of energy plus fat restriction was most effective. Schlundt et al. (16) observed weight losses of 4.6 kg versus 8.8 kg at 20 weeks, and 2.6 kg versus 5.5 kg at month follow-up, both favoring the combination condition. A large dropout rate limited the conclusiveness of these findings. Pascale et al. (17) observed that subjects with type 2 diabetes lost 4.6 kg versus 7.7 kg at the end of 16 weeks and 1.0 kg versus 5.2 kg at 1 year, again favoring the combination of fat and energy restriction; however, the subjects in this study who did not have diabetes had no differences in weight loss on the 2 dietary regimens. Because of these suggestive findings, the field has tended to move toward recommending low-energy, low-fat diets. These studies contrast with the current popular notion of losing weight by restricting dietary carbohydrates. Lowcarbohydrate diets produce initial weight loss as a result of their diuretic effect, but little research has been done on their long-term effect on weight regulation. The effects of other aspects of the diet on long-term weight loss are also important, for example, the effect of energy density or the amount of variety in the diet. McCrory et al. (18) reported that a large variety of sweets, snacks, condiments, entrees, and carbohydrates in combination with a small variety of vegetables was associated with increased intake and greater body weight. These results fit within the laboratory data on sensory-specific satiety showing that individuals will satiate on one food item but suddenly find room to eat more if offered a different type of food (19). In programs such as the Ornish lifestyle change intervention (20), a much lower dietary fat intake (10% fat) is recommended, necessitating greater restriction of food choices. Although weight loss is not a primary focus, large weight losses are obtained (10.9 kg) and maintained (5.8 kg at 5 years). Similarly, there is evidence that vegetarians remain on their designated eating programs far longer than individuals attempting weight loss (21). Perhaps encouraging such lower fat intake or rigid restriction of certain food groups (e.g., meats) will increase long-term efficacy. Food provision and structured meal plans. Behaviorists have long recognized the importance of modifying the home environment as a means of influencing eating behaviors. Stimulus control techniques in which patients are taught to rearrange their home environment to make cues for healthy behaviors more prominent and to reduce cues for unhealthy behaviors are an important component of behavioral programs, as noted above. Recently, behavioral researchers suggested that it might be possible to make even greater changes in the home environment by actually providing patients with the food they should eat in appropriate portion sizes. Jeffery, Wing, and colleagues (22) tested this in a 2-center study with 202 overweight patients. Patients were randomly assigned to 1 of 5 groups: 1) no-treatment control, 2) standard behavioral program, 3) standard behavioral program plus food provision, 4) standard behavioral program plus financial incentives, or 5)

4 CHANGING EATING and EXERCISE BEHAVIOR/Wing, Gorin, and Tate 653 standard behavioral program plus food provisions and financial incentives. Groups 2 5 all received the same 18- month behavioral program and were given comparable goals for fat and energy intake and physical activity. In addition, each week for 18 months, groups 3 and 5 were given a box of food containing all the food they were to eat for 5 breakfasts and 5 dinners each week. The foods provided were quite simple cold cereal, milk, fruit for breakfast; chicken breast, rice, peas, or a frozen entree for dinner. Providing food to participants increased their weight losses at 6, 12, and 18 months. The food-provision groups lost 10.1, 9.1, and 6.4 kg at 6, 12, and 18 months, respectively; the groups given the behavioral intervention without food lost 7.7, 4.5, and 4.1 kg at the 3 time points. The financial incentives did not affect weight loss. Providing food to patients is expensive, so a followup study examined whether weight losses would be similar if participants shared the cost for the food or received meal plans and grocery lists for the 5 breakfasts and 5 dinners (without actually receiving the food). Overweight women (n = 163) were randomly assigned to 1) a standard behavioral program (SBT), 2) SBT plus meal plans and grocery lists, 3) SBT plus food with the costs of the food shared, or 4) SBT plus free food (23). The 3 groups that were given either meal plans or the food all had significantly greater weight losses than did the group with SBT alone, with no differences among these 3 groups (8.0, 12.0, 11.7, and 11.4 kg for groups 1 4, respectively). These superior weight losses appeared to reflect differences in eating behavior. Groups 2 4 all reported increases in the frequency of eating breakfast and lunch and a decrease in snacking, whereas group 1 did not report such changes. Likewise, groups 2 4 reported greater increases than did group 1 in the number of fruits and vegetables, low- and medium-fat meats, breads and cereals, and low-calorie frozen entrees stored in their home. Groups 2 4 also reported less difficulty finding time to plan meals, having appropriate foods available, estimating portion size, and controlling eating when not hungry. Positive results have also been obtained in several other recent studies where patients were given prepared meals (24) or where a liquid meal replacement product (25) was used for 1 or 2 meals/day along with a healthy low-fat dinner meal. These studies suggest that simplifying eating for patients by providing them with structure and models of appropriate meals may promote adherence to weight loss regimens. Changing Exercise The single best predictor of long-term maintenance of weight loss is physical activity (26). Individuals who continue to exercise long term are the ones who are most successful at maintaining their weight loss. The challenge for behavioral researchers is to get overweight individuals to adopt and maintain an exercise program. Home based versus supervised. Having patients exercise under supervised condition allows researchers to better quantify the activity, adjust the intensity or amount of activity over time, and teach participants about warming up, cooling down, etc. However, traveling to a supervised site adds an extra burden for the participant and may discourage continued adherence. Several researchers have compared long-term participation in supervised activity versus home-based activity. In Project Active (27), 235 nonobese (<140% of ideal weight) sedentary men and women aged years were randomly assigned to a lifestyle physical activity program or to a structured activity program. The activity goal for both groups was to increase activity by 3 kcal/kg (which is 1500 kcal/week [6278 kj/week] for a 75-kg individual) during the first 6 months of the program and to maintain an increased exercise level of 2 kcal/kg ( 1000 kcal/week [4184 kj/week]) throughout the remainder of the 18 months. Participants in the structured exercise program were asked to exercise at a supervised facility for the first 6 months. The lifestyle group, which was encouraged to accumulate at least 30 minutes of moderate-intensity activity on most or preferably all days in the week, met weekly as a group for 16 weeks and then biweekly through week 24 to learn cognitive and behavioral skills to increase physical activity. Both groups attended occasional meetings and received newsletters to help them maintain their activity over the 18-month followup. Increases in physical activity were comparable in both groups over the first 6 months, but the supervised group had greater increases in fitness. At 24 months, the groups had similar increases in activity and fitness. Neither group experienced changes in weight but both groups reduced their percentage of body fat. Thus, this study suggested that both lifestyle and supervised activity may be options for increasing activity level and fitness in sedentary adults. Two weight loss studies have likewise compared structured and lifestyle activity programs. Andersen et al. (28) assigned participants in a standard behavioral weight loss program to either a supervised exercise group that attended 3 aerobic dance classes weekly for the first 16 weeks or to a lifestyle group where members exercised on their own and aimed to increase moderate or vigorous activity by 30 minutes/day on most days of the week. Weight losses in the lifestyle and supervised groups were comparable at week 16 (7.9 vs. 8.3 kg); from week 16 to 1-year follow-up, the aerobic group regained 1.6 versus 0.08 kg in the lifestyle group (p = 0.06). A similar comparison of lifestyle versus supervised (group) activity in the treatment of obesity was conducted by Perri et al. (29). Weight losses from months 1 to 6 were comparable in the 2 conditions. However, from month 6 on, exercise participation and weight losses were better in the home exercise group than in the supervised condition. At month 15, the home-based program had an average weight loss of kg whereas the supervised group had a mean weight loss of 7.01 kg. Taken together, these 2 weight loss studies suggest that home-based exercise may be more

5 654 PRESENT KNOWLEDGE IN NUTRITION/8th Edition effective than supervised exercise for long-term weight loss maintenance. Short bouts versus long bouts. The studies with supervised versus lifestyle programs described above may have differed not only in location but also the way in which the activity occurred. In the studies cited above, participants in the supervised exercise conditions completed their activity in 1 bout on each of 3 5 days/week. Those in the lifestyle condition were told to accumulate 30 minutes of exercise each day. These participants may have done this exercise in 1 bout or several short bouts. Because lack of time is considered the greatest barrier to exercise, it may be easier for participants to exercise in multiple short bouts rather than 1 long bout. To test this hypothesis, Jakicic et al. (30, 31) completed 2 weight loss studies comparing programs that prescribed the same amount of lifestyle exercise in either 1 40-minute bout or 4 10-minute bouts 5 days/ week. The first study found better exercise adherence over 6 months and somewhat greater weight losses with the short bouts (30). The second study again found greater exercise participation in the short-bout group for the first several weeks of the study but found no differences between groups from months 6 to 18 (31). These 2 groups had comparable exercise participation, initial and long-term weight loss ( 3.7 kg and 5.8 kg), and long-term improvements in fitness. Thus prescriptions for short bouts of exercise may be particularly helpful during the initial phase of a weight loss program. Providing home exercise equipment. Another approach to promoting adherence to exercise is to provide patients with home exercise equipment. Although it is often noted anecdotally that such equipment receives little use over time, there has been little empirical investigation of this strategy. Jakicic et al. (32) observed a correlation between the number of pieces of activity equipment in the home and activity level. Conceptually, providing exercise equipment to participants (similar to providing food) would help cue the appropriate behavior and reduce barriers related to access, cost, etc. Jakicic et al. (31) examined this strategy in a study of overweight women participating in a behavioral weight loss program. As described above, 1 group of women in this study was asked to complete exercise in short bouts. Another group was given the same exercise prescription and provided with a home treadmill. The group given the exercise equipment maintained a higher activity level from months 13 to 18 of the program and had significantly better weight loss over the 18-month study ( 7.4 vs. 3.7 kg). Thus, this study supports the use of this strategy for improving long-term exercise adherence and weight loss. Decreasing sedentary activities. Several studies have attempted to decrease sedentary activity rather than increase exercise as a way to influence overall activity level and either treat or prevent obesity. This approach has been used only with children although it should also be applicable to adults. Epstein et al. (33) have studied various approaches to the treatment of obesity in children aged 8 12 years and recently compared the effects of decreasing sedentary activities (television, video games), increasing physical activity, and a combination of both. The group that focused on decreasing sedentary activities had the greatest decreases in percentage overweight at 4 months and 1 year ( 18.7% for sedentary, 10.3% for combined, and 8.7% for increased physical activity). The group that was instructed to decrease sedentary activity also reported the greatest increases in their liking of vigorous activity. All groups showed comparable improvements in fitness level. Reducing television viewing as a means to prevent obesity was also examined in a school-based study with 192 children (mean age 9 years) (34). One school was randomly assigned to an 18-lesson, 6-month curriculum designed to decrease television viewing. The children in that school self-monitored their television, video game, and videotape use and attempted a 10-day period during which they did not watch television or play video games. Subsequently, they attempted to decrease these sedentary activities to 7 hours/week. Electronic devices were attached to home television sets to monitor and budget viewing time. The control school received no intervention. Children in the intervention school had statistically significant decreases in television viewing and meals eaten in front of the television. The intervention children also had smaller increases in body mass index (BMI, expressed in kg/m 2, from to 18.67) than the control children (from to 18.81) over the 7-month study. Amount of physical activity. Behavioral weight loss programs have traditionally encouraged participants to gradually increase their physical activity until they achieve 1000 kcal/week (4184 kj/week). (A 68-kg [150-lb] individual could achieve this energy expenditure by walking 16 km/ week [10 miles/week] or 3.2 km [2 miles] on each of 5 days in the week). Recently, researchers have begun to question whether this amount of activity is really optimal for weight loss maintenance. The notion that higher levels of activity may be associated with better long-term weight loss maintenance was first suggested by data collected in the National Weight Control Registry. This registry is a database of >2500 individuals who have lost at least 14 kg (30 lb; mean 30 kg [66 lb]) and kept it off at least 1 year (mean 6 years). Data from the first 784 subjects in the registry (629 women; 155 men) indicated that on average these individuals were expending 2829 kcal/week (11,841 kj/week) in physical activity (35). They expended approximately 1100 kcal/week (4604 kj/week) in walking, 200 kcal/week (827 kj/ week) in stair climbing, and 200, 500, and 800 kcal/week (1837, 2093, and 3348 kj/week), respectively, in light, medium, and heavy sports activities. A similar finding emerged in a study of physical activity and weight loss (36). Post hoc analyses were used to compare self-reported exercise level at 18 months and longterm weight loss maintenance. Subjects (n = 196) were di-

6 CHANGING EATING and EXERCISE BEHAVIOR/Wing, Gorin, and Tate 655 vided into quartiles according to their self-reported activity level at 18 months. Quartiles 1 3, which reported expending kcal/week ( kj/week), did not differ from each other in long-term weight loss maintenance ( 3.0 to 4.8 kg). However, the top quartile, which reported an average of 2550 kcal/week (10.7 MJ/week) of activity, maintained a 7.6-kg weight loss, significantly greater than that of the other three conditions. This high-exercise quartile also reported a pattern of activity quite similar to the registry participants. The top quartile exercisers reported approximately 1125 kcal/week (4709 kj/week) in walking, 250 kcal/week (1046 kj/week) in stairs, and 170, 400, and 600 kcal/week (712, 1674, and 2511 kj/week), respectively, in light, medium, and heavy activity. On the basis of these data, Wing and Jeffery recently started a randomized clinical trial comparing the weight loss effects of a 1000 kcal/week (4184 kj/week) exercise prescription with a group prescribed a 2500 kcal/week (10.5 MJ/week) level of activity. Support for Healthy Eating and Exercise Behavior Behavioral weight loss programs were initially designed with weekly meetings for 10 weeks. As noted above, these treatment programs were gradually lengthened to 16 weeks and then to 20 or 24 weeks. After this phase of weekly meetings, treatment is typically stopped and no further contact occurs until 1 year later. Although researchers were surprised to observe weight regain over this year, this finding should have been anticipated from the behavioral model. It is difficult to change eating and exercise behaviors and maintain these new healthier habits if the environment is not supportive of the new behaviors. Several approaches have been used to provide ongoing support for long-term behavior change. One approach is to continue treatment and therapist contact over longer periods. Perri et al. (37) compared a 20-week behavioral program with a 40-week program. At the end of 20 weeks, weight losses were comparable in the 2 conditions. When the program ended for the 20-week treatment group, these individuals began to regain weight whereas patients in the extended program continued to lose weight from week 20 to 40. At week 40, weight losses averaged 6.4 kg in the 20- week program and 13.6 kg in the 40-week program. When treatment was stopped at week 40, both groups regained weight, but at week 72 there continued to be significant differences in weight loss favoring the longer program (9.8 vs. 4.6 kg). Other behavioral programs providing an entire year of weekly treatment contact have also obtained excellent weight loss results (14.4 kg in Wadden et al. [10] and 10.5 kg in Wing et al.[12]). Reducing treatment contact to biweekly sessions during maintenance also appears effective. Perri et al. (38) found that biweekly contact produced better maintenance of weight loss than no contact. The specific nature of the contact (i.e., whether the sessions included exercise and social support) had less effect on the outcome. The ideal contact schedule, the nature of that contact, and whether the contact must be made by a therapist rather than a peer or research assistant remain unclear. Another approach to providing ongoing support is to include the spouse or friends in the treatment process. Several studies have evaluated the effects of spouse support, with mixed results; a meta-analysis of this literature suggested a small positive effect for spouse involvement (39). Wing et al. (40) developed a spouse support intervention in which participants and their spouses were treated together in a weight loss program (40). Both were given goals for intake and exercise, were instructed to self-monitor, and attended all treatment meetings. In addition, the couples were taught strategies to help each other with weight loss, such as good listening skills and ways to offer or request support. This spouse intervention was compared with a standard behavioral program focused on the patient only. No overall differences in weight loss were found at the end of the treatment program or at 1-year follow-up. A significant interaction effect did emerge, however, in which women in the spouse support intervention and men in the standard behavioral program achieved the best weight loss results. Recently, Wing and Jeffery (41) evaluated 2 new approaches to social support. They recruited participants for a weight loss program and asked them to identify 3 overweight friends who would also like to be in the program and work with them as a team to lose weight. Individuals who identified 3 friends were compared with individuals who were unable or unwilling to identify 3 friends or were not asked to recruit others (i.e., this aspect of the study was not randomized). This natural social support intervention was crossed with an experimental manipulation of social support in a 2 2 research design. The experimental manipulation of social support included intergroup cohesiveness activities and intragroup competitions in which patients competed for money that was returned contingent on maintenance of weight loss. Participants who were recruited with friends and given the social support manipulation had the best outcome, with 95% completing the 10-month study; only 76% of the standard behavioral group (those recruited alone and not given the social support intervention) completed the study. Moreover, 66% of participants recruited with others and given the social support intervention maintained their weight loss in full from month 4 of the program to month 10; only 24% of the standard behavioral group maintained their weight loss in full over the same time frame. Tailoring Treatment to Individual Subgroups Given the difficulty in maintaining weight loss long term, clinicians and researchers have begun to tailor interventions to specific subgroups of the obese population in

7 656 PRESENT KNOWLEDGE IN NUTRITION/8th Edition hopes of improving treatment response. Some examples of tailoring include modifying treatment based on a participant s ethnicity and adapting treatment to address binge eating disorder. Ethnicity. Several studies have suggested that African Americans achieve less weight loss than Caucasians in behavioral weight loss programs (42, 43). This may be due to physiological differences that impede weight loss (44) or to behavioral weight loss programs not being culturally sensitive to the issues affecting African Americans. Several programs have been developed to be more appropriate to the needs of African Americans. Perhaps the most successful is a program developed specifically for innercity African American women with type 2 diabetes (45). The program was based on an active problem-solving approach; program materials were carefully reviewed by a minority panel and included a food guide with ethnic and regional food items. Ten of the 13 participants in this study completed the 18-week program and the 1-year follow-up. Average weight losses were 4.1 kg during treatment and 4.4 kg at 1-year follow-up. Further research is needed to determine how best to tailor programs to make them more appropriate for minority populations. The ethnicity of the other group members, ethnicity of the therapist, locations used for treatment meetings, and specific treatment materials might all influence outcome for minority participants. Binge eating disorder. Of overweight patients seeking weight loss treatment, 30 50% are estimated to meet the diagnostic criteria for binge eating disorder (46, 47). Consequently, it may be important to develop treatments specifically designed for this group of overweight patients. Binge eating disorder is characterized by the presence of binge eating, loss of control over eating, and absence of purging. It is included in the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) as a diagnosis of further study and as an example of eating disorder not otherwise specified. The overall prevalence rate in the general population is 2% and it is evenly distributed between men and women (46). The DSM-IV makes no reference to weight in the binge eating disorder diagnostic criteria; however, it is recognized that there is considerable overlap with obesity, and 50% of individuals with binge eating disorder are overweight. Obese individuals with binge eating disorder differ from the obese individuals without the disorder on several physical and psychological dimensions. Specifically, binge eating is associated with depression, low self-esteem, and poor body image (47, 48). Binge eating is also associated with higher rates of attrition from behavioral weight control programs (43, 49). Given these factors, many have argued that binge eating should be addressed before weight loss to enhance treatment outcome. Treatment has largely focused on the role of dietary restraint and negative affect in the binge eating cycle. Presently, cognitive-behavioral therapy is considered the treatment of choice for this population. It is typically offered in weekly group sessions and produces binge abstinence rates of 40 50% (50). The importance of binge abstinence before weight loss treatment has been emphasized in the literature. In a review of three Stanford-based cognitive-behavioral therapy studies, Agras et al. (51) reported that participants who achieved binge abstinence before weight loss treatment had small weight losses at 1-year posttreatment (4.0 kg) compared with a small weight gain in participants who continued to binge eat (3.6 kg). From this finding, Agras et al. concluded that binge eating cessation is a necessary precursor to long-term weight loss. A study by Marcus et al. (52), however, questions the position that binge eating needs to be addressed independently of weight control. These investigators randomly assigned overweight binge eaters to either a behavioral weight loss treatment, a cognitive-behavioral treatment program for binge eating, or a no-treatment control group. Participants in both active treatments decreased their binge eating frequency, but only participants in behavioral weight loss treatment lost a significant amount of weight. This study suggests that binge eaters might be better served by attending treatment programs that are focused on weight loss rather than binge eating cessation. A retrospective examination of 444 women who participated in behavioral weight loss treatment that included no discussion of binge eating supports this conclusion (53). Sherwood et al. found that binge eaters and nonbingers had comparable shortand long-term weight loss. Further research is needed to determine the influence that binge eating has on weight loss treatment outcome. One area that has received little attention is the timing of treatment for binge eating disorder. All studies have targeted binge eating before weight loss, but perhaps binge eating can be adequately addressed during the maintenance phase of treatment, when lapses and binges are more likely to occur. Media-based interventions for weight loss. Traditionally, behavioral weight loss programs have been offered in face-to-face meetings with health professionals. However, recent research has focused on developing treatment approaches that involve little or no personal contact. Behavioral interventions have been developed for different forms of media including telephone, television, and more recently the Internet and . Such programs have the potential to be more cost effective and more convenient for participants and can be offered to a larger portion of the population. Telephone calls have been used as part of traditional clinic-based programs, often during the maintenance phase of treatment. Phone calls enable therapists to maintain contact with participants but also gradually reduce the number of in-person contacts. The purpose of these calls is to monitor weight, food intake, and exercise. Anecdotal evidence suggests these calls to be helpful. However, in a study where telephone calls were the primary mode of intervention (after 2 initial group meetings), weekly calls did

8 CHANGING EATING and EXERCISE BEHAVIOR/Wing, Gorin, and Tate 657 not produce greater weight losses than no contact (54). Television broadcasts have also been used to deliver behavioral weight loss interventions. In the first study using this approach, a behavioral diet intervention was delivered during a local television broadcast and produced average weight loss of kg/week (55). In another study, a series of 8 1-hour broadcasts of a behavioral group intervention produced weight losses of slightly more than 0.45 kg/week (56). One of the advantages of this approach over the weekly clinic meeting is that the television programs were rebroadcast several different times each week, giving participants multiple opportunities to view the program. Alternately, the broadcast could be videotaped by the participant for later viewing or reviewing. Television broadcasts are a passive mode of communication because the viewer does not participate in the program. However, interactive television changes this 1- way communication into a 2-way interactive process. In interactive telecommunications technology, participants can see and hear the therapist and all other participants. The disadvantage of this approach is that participants must go to an interactive television studio because few people have access to this technology at home. Harvey-Berino (57) investigated interactive television for delivery of a behavioral weight loss program and found it to perform as well as a standard therapist-led in-person program, producing average weight loss of kg/week in 12 weeks. Computer-assisted therapies for obesity began with the development of powerful, lightweight portable computers. These approaches offered a new way for patients to record information and receive quick feedback and reinforcement for incremental steps toward weight loss, often with less direct contact from the therapist. Burnett et al. (58) reported one of the initial studies using this method for behavioral treatment of obesity. Twelve subjects were randomly assigned to either 1) use an interactive microcomputer to enter self-monitoring data, receive feedback about calorie values, and receive praise or further instructions to modify eating contingent on performance or 2) use pencil and paper to record self-monitoring data and to look up calorie values themselves. Participants lost an average of 3.7 kg after 8 weeks in the computer-assisted condition compared with 1.5 kg in the control condition. In another study, participants received behavioral therapy delivered via a hand-held computer or a 1200-kcal/day (5023-kJ/day) frozen foods diet plus the same computerized behavioral therapy that began 5 weeks after the frozen foods diet (59). Participants who followed the frozen foods diet before using the computer to assist with regulation of calorie and fat intake lost significantly more weight after 12 weeks of treatment than did those who did not receive the structured frozen foods diet (5.3 vs. 3.1 kg). It is not clear from this study design whether computer use was required to produce weight loss, because both conditions used the handheld computers even though the timing of computer use was different. Finally, the Internet and offer opportunities to deliver weight loss programs. The great potential of this medium is that it is convenient for participants and allows for an interactive program. Combining behavioral procedures with informational websites produced significantly better weight losses than did informational websites alone in the first study of Internet behavior therapy for weight loss (60). Participants were randomly assigned to receive Internet behavior therapy or an Internet education program. Participants in the education program were given an initial face-to-face meeting and directed to weight loss related websites they could use to develop their own weight loss program but were given no further help to do this. Participants in the behavior therapy program were given this meeting, access to the same website resources, plus access to additional behavioral procedures, all delivered via Internet and , including a sequence of weekly behavioral weight loss lessons, prompting for submission of weekly self-monitoring diaries, personalized feedback, and an on-line bulletin board for social support. Weight losses measured at 12 weeks were significantly greater for the Internet behavior therapy than the education program (4.1 vs. 1.3 kg). Preventing Weight Gain Most behavioral weight loss studies have focused on treatment of overweight individuals. However, there is also a need to develop approaches to help prevent weight gain and reduce the number of individuals who become obese. Epidemiological studies have identified several key times for major weight gain that could be appropriate for prevention efforts. Weight gain prevention in young adults. Williamson et al. (61) noted that young adulthood (age years) poses the greatest risk for major weight gain (BMI gain >5 kg/m 2 or 14 kg over 10 years), which led to several prevention studies conducted in this age group. Klem et al. (62) compared both the acceptability and the effectiveness of a face-to-face weight gain prevention program, a correspondence course, and a minimal intervention control group that was simply sent a weight control brochure. This study was unusual in that interested participants were randomly assigned to a specific treatment and then invited to participate only in that type of program. This approach to randomization allowed the investigators to assess the acceptability of each type of intervention. The main finding of this study was that more women were willing to participate in the brochure or correspondence program than in the face-to-face program (62%, 84%, and 42%, respectively). However, participants who enrolled in the face-to-face program had the largest weight losses (mean losses of 1.9, 1.1, and 0.2 kg for face-to-face, correspondence, and brochure programs, respectively). When both acceptability and efficacy were taken into account, the correspondence condition appeared to produce the best overall outcome. For men who are years old, weight gain may

9 658 PRESENT KNOWLEDGE IN NUTRITION/8th Edition result from decreased physical activity. Thus, prevention of weight gain may best be achieved by focusing on increasing physical activity. Again, however, it is unclear whether a group exercise program requiring participants to travel to an exercise site and attend group meetings would be more or less effective than a home-based exercise program. To assess these approaches, Leermakers et al. (63) recruited 67 men aged years with a BMI of and randomly assigned them to a face-to-face group program, correspondence program, or delayed-treatment control. Men in the group program attended 12 meetings over the first 16 weeks. These meetings included a supervised walking or running session. The men were also encouraged to exercise on their own several days during the week and to gradually increase their activity to the point where they were running or walking 4.8 km/day (3 miles/day) on 4 days/ week at 60 70% of maximal heart rate reserve. The participants were also taught to restrict fat to 20% of energy. The correspondence group received the same educational lessons and the same diet and exercise goals as the face-toface program but received their lessons in the mail and mailed back information about their diet, exercise, and weight. Phone contact between the therapist and the participants also occurred in the correspondence group. These clinic- and home-based programs produced similar weight losses over the 4-month program (1.9 kg and 1.3 kg, respectively) that were significantly greater than the control group (a gain of 0.22 kg). This effect of treatment was observed primarily in the overweight men (BMI 27 30). Changes in physical activity were also greater in the 2 intervention conditions than in the control group. These studies suggest that weight gain prevention may be successfully accomplished by minimal intervention programs involving approaches such as written correspondence and phone contact. An even more minimal intervention was tested recently by Jeffery and French (64). These investigators recruited 228 men and 998 women (including 404 low-income women) aged years and randomly assigned them to a no-contact control group, an education group that was sent monthly newsletters, and an education-plus-incentive group. The education messages stressed frequent self-weighing, eating more fruits and vegetables, decreasing intake of high-fat foods, and increasing physical activity, particularly walking. There was no specific message about reducing energy intake. A return postcard was sent in each newsletter asking participants to report how they had done with these specific behavioral goals and their current weight. Participants in the incentive condition who returned their postcard were entered in a monthly lottery for a $100 prize. The intervention groups reported more frequent selfweighing and an increase in the use of healthy weight loss practices. Changes in behavior were modestly related to changes in weight, but there were no differences between groups in weight gain over the 3-year study or at any time during the study. Thus, education alone may not be sufficient to prevent weight gain. A more structured program involving components such as self-monitoring of energy intake and activity and more frequent interactions with a therapist may be needed to prevent weight gain. Weight gain prevention at time of pregnancy. The period surrounding pregnancy may also be an important time for efforts to prevent weight gain. Although on average women retain only a small amount of the weight gained during pregnancy, there is a great deal of variability in this pattern. For example, in one study of almost 1600 women, 12% of the women retained 4 6 kg at months postpartum and 14% retained 6.4 kg (65). The strongest predictor of postpartum weight retention is weight gain during pregnancy (66); women who gain more than what is recommended are at increased risk of retaining weight postpartum. Butler et al. (67) examined the effectiveness of a weight control intervention designed to reduce the risk of excessive weight gain during pregnancy. Pregnant women were randomly assigned to an intervention condition or control group. The intervention group was given a steppedcare intervention in which minimal strategies (e.g., sending women graphs of their weight) were used initially and then more intensive strategies (phone calls and face-to-face meeting between the therapist and patient) were used if excessive weight gain continued. These intervention efforts were successful in normal-weight women. However, no benefit was observed in overweight women. Alternatively, it is possible to focus body weight related intervention on the postpartum period and target women who still exceed their prepregnancy weight 3 12 months after delivery. Leermakers et al. (68) conducted such a study with 90 women who at 3 12 months postpartum were at least 6.8 kg over their prepregnancy weight. These women were randomly assigned to a 6-month behavioral weight loss program delivered via correspondence or to a no-treatment control group. The correspondence group members were invited to 2 group sessions (at the start of the program and at month 2); they were sent 16 written lessons and were asked to return self-monitoring records and homework assignments. In addition, women received weekly or biweekly phone calls from the therapist. Women in the correspondence program lost 7.8 kg compared with 4.9 kg in the control group and a greater percentage of their excess postpartum weight (79% vs. 44%). Thus, intervention during both the pregnancy and the postpartum period may be helpful in reducing the risk of major weight gain associated with pregnancy. Weight gain prevention at menopause. The perimenopausal period is another time when weight gain is common. Women gain on average 0.5 kg/year (1 lb/year) from age 45 to 55 years. This weight gain seems to reflect aging rather than menopause per se (69). The strongest correlate of weight gain in this age group is decreased physical activity levels. Weight gain during the menopausal transition is of particular concern because it is associated with a worsening in lipid level. As women become menopausal,