Objective: We set out to determine if a primarily Internet-delivered behavioral weight loss intervention produced differential weight loss in African American and non-Hispanic White women, and to identify possible mediators. Design: Data for this analysis were from a randomized controlled trial, collected at baseline and 4-months. Setting: The intervention included monthly face-to-face group sessions and an Internet component that participants were recommended to use at least once weekly. Participants: We included overweight or obese African American and non-Hispanic White women (n=170), with at least weekly Internet access, who were able to attend group sessions. Intervention: Monthly face-to-face group sessions were delivered in large or small groups. The Internet component included automated tailored feedback, self-monitoring tools, written lessons, video resources, problem solving, exercise action planning tools, and social support through message boards. Main outcome measure: Multiple linear regression was used to evaluate race group differences in weight change. Results: Non-Hispanic White women lost more weight than African American women (-5.03% vs.-2.39%, P=.0002). Greater website log-ins and higher change in Eating Behavior Inventory score in non-Hispanic White women partially mediated the race-weight loss relationship. Conclusions: The weight loss disparity may be addressed through improved website engagement and adoption of weight control behaviors
