COMPARISON OF 2-YEAR WEIGHT-LOSS TRENDS IN BEHAVIORAL TREATMENTS OF OBESITY - DIET, EXERCISE, AND COMBINATION INTERVENTIONS

Objective The effects of three cognitive-behavioral weight control int erventions for adults were compared: diet only, exercise only, and a c ombination of diet and exercise. This article reports a-year follow-up data. Design The three interventions were compared in a randomized? e xperimental design. Subjects A total of 127 men and women who were at least 14 kg overweight (according to height-weight tables) were recrui ted from an urban community and assigned randomly to the experimental conditions. Intervention The dietary intervention was a low-energy eat ing plan adjusted to produce a 1 kg/week loss of weight. The exercise component involved training in walking and a home-based program of up to five exercise periods per meek. There were 12 weekly instructional sessions, followed by 3 biweekly and 8 monthly meetings. All sessions were led by registered dietitians. Outcome measures Changes in body we ight. Statistical analyses Analysis of variance for weight changes and repeated measures analysis of variance for weight change trends. Resu lts At 1 year, no significant differences were noted among the three g roups. The diet-only group lost 6.8 kg, the exercise-only Group lost 2 .9 kg, and the combination group lost 8.9 kg (P=.09). During the secon d year, the diet-only group regained weight - reaching 0.9 kg above ba seline; the combination group regained to 2,2 kg below baseline; and t he exercise-only group regained slightly to 2.7 kg below baseline (P=. 36). Repeated measures analysis of variance showed a group-by-time int eraction (P=.001); data for the dieting groups best fit a U-shaped reg ain curve (P=.001). Applications The results suggest that dieting is a ssociated with weight loss followed by regain after treatment ends, wh ereas exercise alone produced smaller weight losses but better mainten ance. The large outcome variability and unequal difficulty of the regi mens across groups limit the generalizability of the findings.