John LK (Carnegie Mellon University), Norton L
(CHERP), Fassbender J
(University of Pennsylvania), Troxel AB
(University of Pennsylvania), Loewenstein G
(Carnegie Mellon University)
Identifying effective strategies for treating obesity is both a clinical challenge and a public health priority due to the health consequences of obesity and its contribution to health disparities. This study tests the effectiveness of financial incentives for achieving clinically significant weight loss.
57 subjects at the Philadelphia VA Medical Center (mean BMI 34.9, 42% African American) enrolled in a 3-arm randomized controlled trial (RCT) in which all subjects were given weight loss targets of 16 pounds in 16 weeks, a counseling session with a nutritionist, and subjects were randomized to: 1) monthly weigh ins; 2) entry into a daily lottery with a 20% chance of winning $10 and a 1% chance of winning $100, with earnings paid only if subjects are below target weights; 3) an option to deposit $.01-$3.00 per day of their own money, matched 1:1 by the investigators, in which subjects receive the sum of both amounts plus a fixed payment of $3.00 each day if below their target weight, but are paid nothing (and lose their deposit) if not. All incentives are disbursed monthly once weights are confirmed in clinic.
The study is fully enrolled with 57 subjects, and data are available for 111 person-months. We observed significantly greater mean weight loss in both incentive groups relative to the control group loss of 2.0 lbs (lottery 11.2 lbs, p = 0.006; deposit contract 12.3 lbs, p = 0.001). Control subjects met monthly weight loss goals at 34.2% of visits, while deposit contract subjects met goals in 82.5% of visits (p = 0.002) and lottery group subjects met goals in 67.7% of visits (p = 0.06). Follow-up has been excellent, with only 7% of participants lost to follow-up to date. Among subjects still under follow-up, across both incentive arms, participants have called in 98% of daily weights, indicating the feasibility of an approach that likely keeps weight loss salient among participants.
Preliminary results from an RCT of financial incentives for weight loss indicate significantly higher weight loss in the incentive arms of the trial.
This approach could have a major impact in reducing the incidence of obesity-related illnesses in both the VA and US populations.