Using an API to Commercialize an Evidence-Based Weight Loss Intervention

The purpose of this study is to test a weight loss app that uses an API to disseminate an evidence-based weight loss intervention. The investigators hypothesize that, over the course of 12 months, participants using the Leaner app will have lost more weight than those in the attention control group. Participants (n=206) will be randomly assigned to use either the intervention app (intervention arm; n=103) or a weight loss app of their choosing (attention control arm; n=103) for 12 months. Assessments will take place at baseline, and 3, 6, and 12 months. Statistical analysis: A linear mixed modeling approach will be used to test the hypothesis. Observed weight vs. time plots will be analyzed for all participants to discern general trends in weight change. The model will include an intervention effect, a time effect, an intervention by time interaction, and a random intercept. In exploratory analysis, investigators will examine weight change across subgroups of interest; investigators will add the subgroup variable and its interaction with the intervention indicator to the primary model. All analyses will be evaluated at the 0.05 significance level.