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/m(2)] 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.