NEW YORK (Reuters) - Obese people may be more likely to slim down if they have money riding on their success through financial incentives -- but the weight might creep back once the monetary carrot is gone, according to a U.S. study.
A program in which people stood to lose cash if they failed to lose weight appeared to motivate them, but the motivation didn't last, the study -- published in the Journal of General Internal Medicine -- found.
All participants received weight loss counseling, but some also signed a "deposit contract," where the funds they deposited in an account were matched and awarded to them at the end of a certain period of time if they achieved their weight loss goals.
If they failed to hit their goal, they lost the money.
People with the "deposit contract" lost an average of nine pounds (4.1 kg) over eight months, while the participants with no money to lose lost only one pound.
"Financial incentives produced significant weight loss over an eight-month intervention," wrote Leslie John at Carnegie Mellon University in Pittsburgh, Pennsylvania, who led the study.
"However, participants regained weight post-intervention."
For the study, John and her colleagues randomly assigned 66 adults with BMIs -- body mass indexes -- of 30 to 40, mostly men, to either have a counseling session with a dietician plus monthly weigh-ins, or the same program plus the deposit contract.
BMI is a measure of weight for height. Obese is classified as 30 and above.
Under the contract, participants could deposit up to $3 per day in an account that the researchers matched dollar-for-dollar. If at the end of the month, they had reached their weight-loss goal -- up to one pound per week -- they could claim the money.
John said the reasoning behind an incentive program is that people respond more readily to the immediate threat of losing money compared to the distant threat of weight-related health problems.
In the study, the threat of losing money did seem to push people to lose more weight. But only 7 of the 66 actually met the study goal of shedding one pound per week over the first 24 weeks of the eight months.
And nine months after the program ended, the financial-incentive group had gained back most of the weight.
Other studies have also suggested incentives may work, John said. Last year, a different research team reported that giving free prepared meals as part of a structured weight loss program helped obese people lose weight.
John said more research is needed to see if the initial success of the plan can be extended. In the real world, money for weight loss could be offered by insurance plans.
"Obesity is hugely costly to insurance companies, so they have financial incentives to look at this," she said, noting that incentives are only really effective in the short- and medium-term.
"I think we still need to show that the weight loss can be maintained," she added.
Reporting by Amy Norton at Reuters Health; editing by Elaine Lies