Abstract
OBJECTIVE: Behavioral weight-loss programs (BWL) provide limited instruction on how to change the environmental context of weight-regulating behaviors, perhaps contributing to regain. Drawing on social ecological models, this trial evaluated a comprehensive weight-loss program that targeted both an individual's behavior and his or her physical and social home environment. METHOD: Overweight and obese adults (N = 201; 48.9 ± 10.5 years; 78.1% women) were randomized to BWL or to BWL plus home-environment changes (BWL + H). Groups met weekly for 6 months and bimonthly for 12 months. BWL + H participants were given items to facilitate healthy choices in their homes (e.g., exercise equipment, portion plates) and attended treatment with a household partner. Weight loss at 6 and 18 months was the primary outcome. RESULTS: BWL + H changed many aspects of the home environment and produced better 6-month weight losses than BWL (p = .017). At 18 months, no weight-loss differences were observed (p = .19) and rates of regain were equivalent (p = .30). Treatment response was moderated by gender (6 months, p = .011; 18 months, p = .006). Women lost more weight in BWL + H than BWL at 6 and 18 months, whereas men in BWL lost more weight than those in BWL + H at 18 months. Partners, regardless of gender, lost more weight in BWL + H than BWL at both time points (ps < .0001). CONCLUSION: The home food and exercise environment is malleable and targeting this microenvironment appears to improve initial weight loss, and in women, 18-month outcomes. Research is needed to understand this gender difference and to develop home-focused strategies with more powerful and sustained weight-loss effects.