Cash for pounds seems to work

The chance to win or lose $20 a month enticed dieters in a yearlong study to drop an average of 9 pounds — four times more weight than others who were not offered dough to pass up the doughnuts. The new study, done with Mayo Clinic employees, was the longest test yet of financial incentives forweight loss. Doctors think it succeeded because it had a mix of carrots and sticks — penalties for not losing weight, multiple ways to earn cash for succeeding, and a chance to recoup lost money if you fell off the "diet wagon" and later repented.

The diet study involved 100 obese employees at Mayo Clinic but was not a workplace wellness program. Half were given weight-loss counseling, monthly weigh-ins and a three-month gym membership. The others had those things plus financial incentives.

The aim was to lose 4 pounds a month up to a goal that depended on their starting weight. If they failed, they paid $20 into a kitty. If they succeeded, they got a voucher to collect $20 when the study ended. Part of the kitty was used to pay the rewards. The rest was put into a lottery that anyone could win, whether they had made their weight-loss goals or not.

Participants in the financial incentives group also earned $10 a month and lottery "tickets" for coming to monthly weigh-ins and texting their weights to study leaders each week. So people could have lost as much as $240 or won as much as $360, plus what built up in the lottery fund.

After a year, 27 of the 50 financial incentive participants came out ahead moneywise. About 62 percent of them completed the study versus 26 percent of the other group. The incentives group lost a little more than 9 pounds on average, compared to 2.3 pounds for the others.

The results are promising, but people may need to lose more than 9 pounds to make a big difference in health.