Randomized controlled trial of financial incentives during weight-loss induction and maintenance in online group weight control.

OBJECTIVE: This study examined the impact of a financial incentive scheme integrating process and outcome incentives across weight-loss induction and weight maintenance on 18-month weight outcomes. METHODS: This was a randomized controlled trial. Participants with overweight or obesity (n = 418; 91% female; 28% racial/ethnic minority) were randomized to an 18-month, online, group-based behavioral weight-control program (Internet-Only) or the same program with financial incentives provided for 12 months, contingent on self-regulatory weight-control behaviors (self-weighing, dietary self-monitoring, and physical activity) and weight-outcome benchmarks (Internet+Incentives). No financial incentives were provided from Months 13 to 18 to examine the durability of weight-control behaviors and outcomes without incentives. RESULTS: Weight-loss induction at Month 6 was significantly greater for Internet+Incentives than Internet-Only (6.8% vs. 4.9%, respectively, p = 0.01). Individuals receiving incentives were significantly more likely to maintain weight loss ≥ 5% at Month 12 (45% in Internet+Incentives vs. 32% in Internet-Only, p < 0.02) and remain weight stable (39% vs. 27%, respectively, p < 0.01). Internet+Incentives participants also reported significantly greater behavioral engagement through Month 12. However, once incentives ceased, there were no differences in sustained weight outcomes (Month 18), and engagement declined dramatically. CONCLUSIONS: Despite promoting greater treatment engagement and initial weight loss, financial incentives as offered in this study did not promote better extended weight control.