Rewarding groups for losing weight more effective than rewarding individuals

The study, which appears in the April 2 issue of the Annals of Internal Medicine, enrolled employees of the Children's Hospital of Philadelphia who had a body mass index (BMI) of 30 to 40 kg/m2. It compared two weight-loss incentive strategies. The first strategy paid individual employees $100 per month for each month that they met their weight-loss goals. The second strategy offered groups of five people $500 per month for each month they met their goals. In the second group, employees who met their goals received the balance of money unearned by employees who did not meet their goals. At the end of the six-month study, the group cash incentive led to a weight loss that was approximately seven pounds greater than the individual cash incentive.

An estimated 86 percent of large employers are using some kind of financial incentive to encourage their employees to lose weight. "To our knowledge, our study is the only randomized trial to compare the effects of group competition-based and individual incentives for weight loss," said the study's senior author, Kevin Volpp, MD, PhD, professor of Medicine and director, Center for Health Incentives and Behavioral Economics at the Leonard Davis Institute of Health Economics at Penn. "These new findings open up the possibility of more effective interventions for getting people to lose weight and could apply to other areas of serious health concern, such as smoking, as well."

The greater effectiveness of the group incentive was likely tied to the opportunity to earn a reward larger than $100 for achieving a weight-loss goal, and also the competition involved in such designs. The fact that most group members did not meet their weight-loss goals in most months likely provided additional inspiration by leaving a larger reward for those who did meet their goals.

"Under the Affordable Care Act, employers will be able to offer even larger financial incentives than they do now to encourage healthy behaviors among their employees," said co-author David Asch, MD, MBA, professor of Medicine and executive director of the Penn Medicine Center for Innovation. "Our study demonstrates that how one offers the incentive is critically important. A lot of employers, insurers, and health care institutions are rolling out incentive programs now, and with a little design help they can make those programs much more effective."

The study's first author is Jeffrey Kullgren MD, MS, MPH, a former Robert Wood Johnson Clinical Scholar at the University of Pennsylvania who is now an assistant professor at the University of Michigan. Additional Penn co-authors were Andrea B. Troxel, ScD; Laurie A. Norton, MA; Lisa Wesby, MS; Yuanyuan Tao, MS; and Jingsan Zhu, MS, MBA.

The primary funding source for the study was the National Institute on Aging (Grant RC2103282621). Support was also provided by the Department of Veterans Affairs and the Robert Wood Johnson Foundation.