Financial incentives appear to be effective for achieving short-term weight loss, according to a study released on December 9, 2008 in JAMA.

The obesity epidemic in the United States is well recognized. “In 2004, 71 percent of U.S. adults were overweight or obese according to standard definitions, and at present obesity falls just behind smoking as a preventable cause of premature death,” the authors write. They continue, pointing out that many behaviors predict obesity: “Although many variables contribute to the increase in obesity prevalence in the United States, behavioral economics has identified several patterns of behavior that help explain why people engage in self-destructive behavior, including the tendency to put disproportionate emphasis on immediate gratifications, such as the pleasure of eating, relative to the much smaller emphasis put on delayed benefits, such as enjoying good health.”

They claim that “new strategies are needed to help reduce the rate of obesity in the U.S. population.” To investigate this, Kevin G. Volpp, M.D., Ph.D., from the University of Pennsylvania School of Medicine and the Wharton School, VA Center for Health Equity Research and Promotion, Philadelphia, and colleagues, performed a randomized trial implementing two incentive based approaches for losing weight and one control approach. A total 57 participants were randomized to one of these approaches and monitored for weight loss.

One incentive-based approach was based on a lottery system to distribute , in which subjects received a target weight, and received earning if they achieved the target weight. The other incentive-based approach required the subjects to invest their own money, which they would loss if they did not achieve their weight loss goals. All participants were given a goal weight loss of 16 pounds in the 16 week period.

The authors report their results: “The incentive groups lost significantly more weight than the control group (mean [average] 3.9 pounds).” They continue: “Compared with the control group, the lottery group lost a mean of 13.1 pounds and the deposit contract group lost a mean of 14.0 pounds. About half of those in both incentive groups met the 16-pound target weight loss: 47.4 percent in the deposit contract group and 52.6 percent in the lottery group, whereas 10.5 percent in the control group met the 16-pound target.”

The financial gains with each approach also differed: “Over the course of the 16-week study, the average amount of money earned in weight loss incentives was $378.49 in the deposit contract condition and $272.80 in the lottery condition.” In a seven month follow-up, the participants in both of the incentive groups gained weight, but still weighed less than they did at the start of the study.

The authors conclude that this may be an avenue of intervention worth pursuing in weight loss management: “In conclusion, incentive approaches based on behavioral economic concepts appear to be highly effective in inducing initial weight loss. However, this weight loss was not fully sustained and further work is needed to test the effectiveness and cost-effectiveness of these approaches in achieving sustained weight loss.”

Financial Incentive-Based Approaches for Weight Loss: A Randomized Trial
Kevin G. Volpp, MD, PhD; Leslie K. John, MS; Andrea B. Troxel, ScD; Laurie Norton, MA; Jennifer Fassbender, MS; George Loewenstein, PhD
JAMA. 2008;300(22):2631-2637.
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Written by Anna Sophia McKenney