Study Suggests Financial Incentives Work to Reduce Weight among Obese and Overweight Veterans

KEY FINDINGS:

• Veterans participating in two weight loss strategies based on financial incentives lost significantly more weight than veterans in the control group. About half of the veterans in the incentive groups met the 16-lb target weight loss, whereas only 10.5% of veterans in the control group met the target.
• Substantial amounts of weight were regained between the end of the weight loss phase and the follow-up three months later. However, incentive participants weighed significantly less at seven months than at the study start compared to veterans participating in the control group.
• A key challenge in weight loss interventions is to both attain the initial weight loss and to maintain it over periods of 12 months or more. The authors suggest further testing of longer-term use of these incentives to determine whether longer use would lead to sustained weight loss.

ARTICLE SUMMARY:
In 2004, 71% of adults in the United States were overweight or obese, and obesity falls just behind smoking as a preventable cause of death. New strategies are needed to help reduce the rate of obesity. Investigators in this study designed two approaches based on financial incentives for losing weight: 1) a lottery-based approach in which participants played a lottery and received earnings if they achieved or lost more than the target weight, and 2) a deposit contract approach in which participants invested their own money, which was lost if they failed to achieve weight loss goals. Veterans participating in the deposit contract incentive were given the opportunity to contribute up to $3 per day that was matched by the study, along with a daily fixed payment of $3, all of which could be collected at the end of the month if they met or exceeded the weight loss goal. However, money would be forfeited if goals were not achieved. Forfeited money was put into a pool that was divided equally among deposit contract participants who lost 20 lbs or more over 16 weeks. Participants in the lottery group were eligible for a daily lottery prize (infrequent large payoffs, e.g., $100 and frequent small payoffs, e.g., $10), if they were at or below their target weight. The effects of these incentives in achieving weight loss were tested over 16 weeks among obese and overweight veterans at one VAMC: 19 veterans each in the lottery-based and deposit contract approaches, compared with 19 veterans in a control group (monthly weight monitoring with no incentives).

LIMITATIONS:

• Because the study population consisted of veterans who volunteered to participate, study participants were likely more motivated than the average person with obesity.

AUTHOR/FUNDING INFORMATION:
Although veterans participated in this study, it was not funded by VA. Dr. Volpp and Ms. Norton are part of HSR&D’s Center for Health Equity Research and Promotion, Philadelphia.

Volpp K, John L, Troxel A, Norton L, Fassbender J, Loewenstein G. Financial Incentive-Based Approaches for Weight Loss: A Randomized Trial. JAMA 2008 Dec 10;300(22):2631-37