Use of Medication to Improve Weight Loss in Suboptimal Early Responders to Behavioral Treatment

This is a two-phase study. Phase 1 will evaluate obesity-related behavioral and biological characteristics as potential predictors of response to behavioral treatment (BT) for weight loss. Phase 2 is a double-blind, placebo-controlled, RCT to test whether adding weight loss medication to BT improves 24-week weight loss, as compared to BT with placebo, in subjects identified as having suboptimal early weight loss after 4 weeks of individual behavioral weight control. All participants, regardless of their early weight loss, will receive the same BT program of diet, physical activity, and behavior therapy for weight loss for an additional 24 weeks (28 total weeks of treatment).