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TUESDAY, Dec. 9, 2008 (Health.com) — Want to shed some pounds? You’re more likely to be successful if you stand to gain—or lose—some money.

In a new study, overweight or obese dieters who were trying to shed weight lost 13 to 14 pounds in four months if they stood to win or lose a bit of money. The dieters who had no motivation—other than to look better and feel healthier—lost only about 4 pounds.

However, the results were less dramatic after seven months. The cash-incentive group regained weight, for a total 6- to 9-pound weight loss, compared to 4.4 pounds in those who did not have money at stake, according to the study published Tuesday in the Journal of the American Medical Association.

Kevin Volpp, MD, PhD, one of the study’s authors and the director of the Center for Health Incentives at the Leonard Davis Institute for Health Economics, in Philadelphia, says providing a small financial incentive helped people forget what they were giving up—fatty fare like burgers and fries, rich desserts, or alcohol.

This mix of frequent rewards, both large and small, helped dieters to stay on track—and on the scale. “It was a tangible reminder for why they are changing their behavior,” Dr. Volpp says.

The study included 57 people ages 30 to 70—almost all men—who were overweight or obese. One group contributed between $0.01 and $3 to a fund each day, which was matched by researchers. If they met their weight-loss goal, the money was refunded at the end of the month. A second group had no financial incentive, and a third group qualified for daily $3 prizes, plus less frequent $10 to $100 prizes, if they lost weight.

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