Efficacy of Environmental And Acceptance-Based Enhancements to Behavioral Weight Loss Treatment: The ENACT Trial

OBJECTIVE This study was designed to compare weight loss through a traditional behavioral treatment (BT) approach that integrated skills for managing the obesogenic food environment (BT + E) with an approach that integrated environmental and acceptance-based skills (BT + EA). Moderators were examined as an exploratory aim. METHODS Adults (N = 283) were randomly assigned to treatment condition and provided with 26 group-based sessions over the course of 12 months. Weight was measured in the clinic at months 0, 6, and 12. RESULTS Change in weight over time did not significantly differ by condition. However, race significantly moderated the effect of condition on weight loss (P = 0.04), such that African-American participants lost less weight than non-Hispanic white participants in the BT (6.2% vs. 11.5%) and BT + E conditions (6.6% vs. 12.2%), but weight loss in these two groups was similar in the BT + EA condition (9.4% vs. 11.5%). Among African Americans, rates of achieving a clinically significant weight loss (i.e., > 5%) at 12 months were higher in BT + EA (80%) than BT (57%) or BT + E (48%) (P = 0.04). CONCLUSIONS This innovative behavioral approach shows promise for treatment of African Americans, which is notable given the lack of progress to date addressing racial disparities in obesity intervention efficacy.