Abstract 11441: The Smarter Weight Loss Intervention Trial: The Effect of Real-Time Feedback on Weight Loss at 12-Months

Introduction: Obesity prevalence exceeds 40%, yet availability of standard behavioral treatment to those with overweight/obesity is limited; moreover, its in-person format and intensity is unappealing to some. Evidence indicates that providing feedback (FB) to self-monitoring (SM) of lifestyle behaviors improves outcomes. We tested the efficacy of delivering tailored FB messages remotely compared to no FB on weight loss outcomes. Hypothesis: At 12 mos participants receiving feedback (SM+FB) would have greater weight loss than those in the SM only group. Methods: We randomized 502 adults with overweight/obesity to either SM+FB (n=251) or SM alone (n=251). We delivered 3 smartphone pop-up messages/day to SM+FB group that were tailored to SM entries and delivered at random during waking hours. SM tools included a smartphone app to self-report diet, Fitbit Charge 2 to monitor physical activity, and a digital scale to track weight. All had a 90-min 1:1 intervention session with a dietitian at baseline that focused on behavioral changes to achieve weight loss. Percent weight loss from baseline and percentage of participants having ≥5% weight loss at 12 mos were compared between treatment groups using an intention-to-treat approach. Missing assessment weights at 12 mos were imputed using participants’ weight tracking data. Results: The sample was mostly female (79.5%) and white (84.3%) with a mean BMI of 33.1 ± 3.93 kg/m 2 . Based on the linear mixed modeling of weight, only a significant time main effect was observed ( F = 61.43, P <.0001), suggesting that on average there was significant change in weight over the 12-month period. Both groups had similar percent weight loss at 12 mos, SM+FB group: mean [95% CI] -2.12% [-3.04, -1.20] and SM group: -2.39% [-3.32, -1.47] (P= .679). The percentage achieving ≥5% weight loss at 12 mos was also similar between the groups (26.3% for the SM+FB group and 29.1% for the SM group) (P= 0.485). Conclusions: The results did not support our hypothesis that participants in the SM+FB group would show greater weight loss at 12 mos than those in the SM group; however, the data support clinical efficacy for both approaches to a weight loss intervention.