TUESDAY, April 2, 2013 (HealthDay News) -- Paying people to lose weight works, but some sort of competition or group effort may make it work even better, a new study reports.
The research showed how two company-sponsored weight-loss programs produced different results depending on how the rewards were structured.
The study, published April 1 in the journal Annals of Internal Medicine, demonstrates that when it comes to designing programs to help employees lose weight, details about how incentives are offered and how much cash is up for grabs can make a big difference in short-term outcomes.
The sustainability of weight loss accomplished in such efforts remains unclear, however.
In one group of five participants, the prize of meeting an individual weight-loss goal was $100, no more or less. In another, also with five members, the prize was $100, but with a chance at more if other members didn't succeed. The latter group had nearly three times the weight loss as the former.
Dr. Jeffrey Kullgren, the lead author of the study and an assistant professor of internal medicine at the University of Michigan, became interested in how to motivate people to lose weight from his work as a practicing primary-care physician. "I realized that behavior change is really hard," he said. With more than 80 percent of large employers thinking of offering some form of financial incentives to help people modify risk factors, he said it was important to see what really works.
"A lot of innovation is going on without a lot of evidence," Kullgren said. "The trains have left the station, so we're trying to be sure [programs] help people get where they need to be."
His research follows on the heels of a study, presented last month at the American College of Cardiology annual meeting in San Francisco, that showed those who got $20 a month for shedding four pounds -- or had to pay $20 for not losing the weight -- were more likely to reach weight-loss goals.
Kullgren's study involved 105 employees of the Children's Hospital of Philadelphia who were between the ages of 18 and 70 and considered obese. The goal for everyone was to lose a pound a week.
The researchers studied two types of incentive strategies: a group incentive and an individual one. In the individual approach, employees were offered $100 for each month they met or exceeded weight-loss goals. For the other, groups of five employees were offered $500 a month to be divided equally among only the members who met their goals. Those who didn't meet their goals received no money. The five-member groups had no way of learning each other's identities, so they couldn't intentionally tempt or discourage each other in an effort to personally win a bigger share of the pie.
The potential upfront cost to an employer was the same for either strategy. A control group was created to compare the two strategies to one in which people had no financial incentive. Those participants got a link to a national weight-control website, along with monthly weigh-ins supported by email or text reminders.
After 24 weeks, participants in the group-incentive plan lost about 7 pounds more on average than those who were in the individual plan, and an average of almost 10 pounds more than those in the control group. Twelve weeks after the program ended, those in the group incentive plan maintained more weight loss than those in the control group, but not more than those in the individual incentive plan.
What is the psychology behind the study results? Price matters, said Jason Riis, who wrote an editorial accompanying the research. "Some amount of money constantly at stake each month -- a goal and a reward -- does seem to be a mechanism to help people make slightly better decisions," said Riis, an assistant professor of business administration at Harvard Business School.
For those who don't have access to employer-based programs, Riis suggested people create incentives between themselves and friends. He recommended Stickk.com, created by a Yale University economics professor who came up with the idea of opening an online "commitment store."
Participants sign contracts obliging them to achieve their personal goals, such as losing weight, with the risk of a financial penalty if they fail.
Whatever the approach, the key to maintaining weight loss over the long term remains elusive, Riis said. "We're a long way from knowing the answers to that," he said.
Learn more about how to maintain a healthy weight at the U.S. Centers for Disease Control and Prevention.