Behavioral weight loss in emerging adults: Design and rationale for the Richmond Emerging Adults Choosing Health (REACH) randomized clinical trial

Background: In the U.S., over 40% of 18-25 year olds meet criteria for overweight or obesity. Yet, no large-scale trials have targeted this age group for behavioral weight loss (BWL). Formative data revealed that existing BWL programs do not meet their unique needs and identified motivation as a fundamental barrier for weight management. The goal of the Richmond Emerging Adults Choosing Health (REACH) trial was to test the efficacy of two mHealth lifestyle interventions specifically focused on enhancing motivation, relative to adapted standard. Methods: Participants (N = 381, 18-25 years, body mass index 25-45 kg/m2) will be randomized to 1) adapted BWL (aBWL), 2) aBWL + self-determination theory (aBWL+SDT), or 3) aBWL + behavioral economics (aBWL+BE). All arms will receive a 6-month intervention, delivered via one group session and one individual session, followed by an mHealth platform. Assessments will occur at baseline, 3-months, 6-months (post-treatment) and 12-months (following a no-contact period). The primary aim is to compare weight loss outcomes at 6 months. Secondary aims include changes at 6-months in physical and behavioral cardiometabolic risk factors, as well as psychosocial measures. We will also explore weight loss maintenance, change in hypothesized mediators, and moderators of treatment response. Discussion: REACH is the first large-scale BWL trial designed specifically for emerging adults. Further, it will be the first trial to compare a lifestyle intervention grounded in self-determination theory to one rooted in behavioral economics. If clinically significant reductions in adiposity are achieved, findings could inform a scalable treatment model to meet the needs of this vulnerable population. Trial Registration: NCT02736981