Theory-based Psychosocial Factors that Discriminate Between Weight-loss Success and Failure Over 6 Months in Women with Morbid Obesity Receiving Behavioral Treatments
Purpose: To improve success rates of behavioral weight-loss treatments, a better understanding of psychosocial factors that discriminate between weight-loss success and failure is required. The inclusion of cognitive–behavioral methods and manageable amounts of exercise might induce greater improvements than traditional methods of education in healthy eating practices. Methods: Women with morbid obesity [body mass index (BMI) ≥40 kg/m2] were recruited for a treatment of supported exercise paired with either a cognitive–behavioral or an educational approach to eating change over 6 months. They were classified as either successful with (i.e., at least 5 % loss; n = 40) or failed at (no loss, or weight gain; n = 43) weight loss. Discriminate function analysis incorporated theory-based models of 1 (self-efficacy), 5 (self-efficacy, self-regulation, mood, physical self-concept, body satisfaction), and 3 (self-efficacy, self-regulation, mood) psychosocial predictors at both month 6, and change from baseline–month 6. Results: All three models significantly discriminated weight-loss success/failure (66, 88, and 87 % for success; and 81, 87, and 88 % for failure, respectively). Self-regulation had the strongest correlations within the multi-predictor models (0.90–0.96), and all variables entered were above the standard of 0.30 set for relevance. Participants in the cognitive–behavioral nutrition group demonstrated significantly greater improvements in all psychosocial variables and success with weight loss. Completing at least two sessions of exercise per week predicted success/failure with weight loss better than overall volume of exercise. Conclusions: New and relevant findings regarding treatment-induced psychosocial changes might be useful in the architecture of more successful behavioral weight-loss interventions.