Thirty-six RCT articles were examined to evaluate whether behavior therapy provides additional benefits beyond other weight loss approaches. The acceptable RCTs compared behavior therapy plus another weight loss strategy to that weight loss strategy without behavior therapy.
Rationale: Four RCTs addressed the question of whether behavior therapy, in order to reinforce a healthy diet, provides additional benefits above and beyond other weight loss approaches. Three studies compared behavior therapy plus dietary intervention to a dietary intervention alone (436, 476, 477). No studies were found that examined the added benefit of behavior therapy when combined with either physical activity or diet and physical activity. One study was found that compared behavior therapy to drug therapy (478). One study compared 36 obese women in one of three groups of 12 participating in a 16-week intervention: (1) individual counseling; (2) group counseling; and (3) group counseling plus behavior therapy. All groups lost weight at the end of treatment, and there were no significant differences among the groups. By the 1-year follow-up, participants in groups 1 and 3 were equally successful in maintaining weight loss, while most participants in group 2 regained most of their weight (476).
Other studies examined the effect of VLCD alone and in combination with behavior therapy (436, 477). Subjects were randomly assigned to either: (1) VLCD alone; (2) behavior therapy plus LCD (1,000 to 1,200 kcal), denoted as the behavior therapy-alone group; or (3) VLCD plus behavior therapy (combined treatment). They were assessed at the end of treatment and at 1- and 5-year follow-ups. At the end of treatment, and at the 1-year follow-up, weight loss was significantly greater for the combination group as compared to the other two groups. About one-third of those receiving behavior therapy (either in combination with an LCD or VLCD) were able to maintain their full end-of-treatment weight loss at 1 year, compared to only 5 percent of those in the diet-alone group. By the 5-year follow-up, the mean weight loss was not significantly different across groups.
Thus, although the weight loss results of behavioral treatment in combination with either an LCD or VLCD were quite good at the end of treatment and at the 1-year follow-up, they were not maintained by 5 years. These results may well have been due to the infrequent practice of the behavioral strategies by the subjects. Wadden and colleagues recommended that patients participate in a 6- to 12-month weight maintenance program after weight loss (which subjects did not do in the study described above), and that if they experience a gain of 5 kg (11 lb) which they cannot reverse on their own, that they should reenter a weight loss therapy program.
One study assessed the short- and long-term weight loss of behavior therapy, fenfluramine, or a combination of the two in 120 obese women (478). Patients in the drug group and those in the combined drug plus behavior therapy group lost significantly more weight than did the group that received behavior therapy only and the control group; the drug-only group and combination group did not differ from each other at the end of the 6-month treatment. However, at the 1-year follow-up, significantly less weight was regained by the patients in the behavior-therapy-only group compared to the combined treatment group and the pharmacotherapy group, resulting in significantly better overall net weight loss. Results of this study suggest that the various interventions had different effects at the end of treatment and at follow-up.
To summarize, three of the four studies demonstrated that behavior therapy, when used in conjunction with other weight loss approaches, was more effective in reducing weight or delaying weight regain, either at the end of treatment or at the 1-year follow-up or both (476-478). Behavior therapy was not better in its effect on weight loss at the 5-year follow-up.
No RCTs examined the additional effect of behavior therapy combined with diet and physical activity on cardiorespiratory fitness or abdominal fat.