In a nation struggling with soaring obesity rates, there is no gimmick that Americans haven't tried to lose weight. But what if someone paid you to keep the pounds off? Could it work?
New research from the University of Pennsylvania School of Medicine has found that cash could be the ultimate incentive in weight loss. In a study of 57 people seeking to lose weight over four months, those who were paid to shed pounds lost more than those who were not.
The study, released yesterday in The Journal of the American Medical Association, is based on a well-known premise in psychology: Positive reinforcement can help people change their behavior. Individuals respond best when reinforcement is immediate and when the incentive represents something of value to them.
Changing health habits is tough because it requires people to make sacrifices now that might not benefit them until much later, said Dr. Kevin G. Volpp, associate professor at the University of Pennsylvania School of Medicine and the study's lead investigator.
Simply imploring people to lose weight to improve their health rarely works, he said, but incentives can provide a tangible boost during what can often be a long weight loss journey.
"We know that lowering weight can help diabetes and other health problems, but it's hard to figure out how, in the here and now, does this affect me," he said. "Incentives provide a reinforcement mechanism that helps people to take actions in the short term that are in their long-term best interests."
Investigators split study participants into three groups and challenged them to lose a pound a week.
One group took part in a lottery system, in which participants had the chance to win up to $100 a day for meeting daily weight loss goals.
Another used what researchers called a deposit contract system, in which participants bet their own money - between a penny and $3 per day - that they would meet their goals. If they did, researchers matched their winnings. If they did not, their money was forfeited and put into a pool to reward people who met their goals.
The third, a control group, received no money.
Participants weighed themselves every morning and called in results to researchers. Everyone but the control group then received text messages notifying them of their progress and how much money they could expect. Participants were paid every month.
At the end of 16 weeks, the lottery group lost an average of 13.1 pounds; the deposit group 14 pounds; and those who received no cash 3.9 pounds.
"I think it was as successful as we have hoped it would be," Volpp said. "I think it shows that these types of incentive programs that involve daily feedback are feasible."
But the long-term benefit of the approach is questionable; few participants sustained their weight loss. At a seven-month follow-up, members in each group had gained back some of the weight.
Volpp said a longer study could produce more lasting results.
Dr. Lawrence J. Cheskin, director of the Johns Hopkins Weight Management Center, agreed that monetary incentives can be effective. But he questioned whether the study's design could hold long-term promise.
"Does it continue to work, or do you become desensitized?" he said. "When you are at a job and you get a 10 percent raise, what happens in a few months when you get another 10 percent raise? It's not so special that second time."
Volpp maintains that paying people works. He took part in a study two years ago that offered people money to attend smoking-cessation classes. People who received money were more likely to complete the program and to quit smoking over the short term than those who were not paid.
Volpp is the director of the Center for Health Incentives at the Leonard Davis Institute of Health Economics, which studies health behaviors and their relation to health care costs. He received funding to pay study participants from the U.S. Department of Agriculture, the Hewlett Foundation and the National Institute on Aging.
He said that if businesses and insurers invested in financial incentives, they could save money on health care by reducing the need for expensive treatment later.
Cheskin thinks the model could help people lose weight without money by offering other types of encouragement that are meaningful to participants. The key to any effective incentive is constant reminders and attention, he said.
For instance, people lose weight on the reality show The Biggest Loser not only because they could get rich doing so, he said.
"Of course, the money is very substantial, but you're on TV for God's sakes," he said. "What more public measure feedback can there be? It's one thing not to succeed in front of you and your beloved. It's another thing not to succeed before the world."