Group-Based Incentives for Weight Loss Produce Better Results

    • April 22, 2013

More than a third of Americans are obese, according to the Centers for Disease Control and Prevention and, for many, that extra weight contributes to a range of health problems, including diabetes, hypertension, some forms of cancer, heart disease, joint problems, and more. Taken together, those health issues drive costs for the nation's health care system—as much as $210 billion annually, according to a 2012 study by the Robert Wood Johnson Foundation (RWJF) and the Trust for America's Health.

Employers have a particular stake in combatting obesity: It affects the health of their workforce, and has a direct impact on health insurance premiums. So in recent years, many employers have taken a more active role in encouraging their employees to get and stay healthy. Some have begun offering financial incentives to employees if they lose weight, reasoning that sick leave not taken and lower health insurance costs will more than make up for the upfront cost of the incentives.

But how should employers structure their incentive packages to have the greatest impact? What is the most cost-effective incentive program? Those are questions that Jeffrey Kullgren, MD, MS, MPH, an alumnus of the RWJF Clinical Scholars program (2009–2012) and colleagues examine in a new study, published April 2, 2013, in the Annals of Internal Medicine.

"Financial incentives are being offered more and more frequently across the country, particularly by large employers, to motivate healthy behaviors," Kullgren says. “Changing these behaviors can be hard for individuals, in part because the benefits accrue far in the future. So incentives provide a tangible short-term reward that would, ideally, help people stay on track while they build new habits and self-efficacy. But we have very little data about which incentive approaches work and which don’t … Our study is one of few to actually test incentives in a real-world setting."

Group or Individual?

Kullgren and his colleagues focused their study on two broad incentive models, one that offered specific incentives to individuals to meet certain weight goals, and one that offered incentives to groups of five employees to meet those same goals. All participants were given information to support their weight-loss efforts, along with a monthly weigh-in. A third group served as a control group, with access to all the same information as the rest of the participants, but with no incentives offered.

The researchers partnered with Children's Hospital of Philadelphia, recruiting more than 100 obese participants from among the hospital's employees. Each participant’s goal was to lose 4 pounds every four weeks for 24 weeks.

The study called for incentives of $100 for each employee who met or exceeded weight goals, but those incentives were distributed differently for the two test groups. Those participating as individuals would receive $100 if they met their weight goal. But those participating as members of a group had a different structure. If any of the five members of the group met or exceeded the goal, the group would receive $500, to be divided equally among all members who met their goals. As a result, group participants who lost the designated 4 pounds could earn as "little" as $100 and as much as $500 every four weeks.

"We wanted to engender competition," Kullgren says, so that employees were "essentially competing for the same pot of money." He contrasts the model, however, to the winner-take-all approach used on television's Biggest Loser competition. "One thing we liked about our design, relative to the Biggest Loser, is that on the television show, the most successful person gets the entire incentive. That means that a lot of people who meet their goals don’t receive a reward, which could be discouraging for them. Our approach harnessed competition, but in a way that offered a reward to everyone who met their weight loss goal."

Another significant element of the design was that participants who missed their goals in a given four-week period were still eligible for incentives at the next weigh-in—a design feature that Kullgren says was intended to keep participants engaged in the program even if they missed a goal or two.

Group Incentives Deliver the Goods

The results of the test affirmed the value of monetary incentives as a motivational tool, and demonstrated that the group incentive model used in the study produced even more bang for the employer's buck than individual incentives. After 24 weeks, group-incentive members lost nearly 10 pounds more, on average, than the members of the control group, and seven pounds more than the individual-incentive participants.

Kullgren and colleagues write:

The greater effectiveness of the group incentive could be due to several factors. The opportunity to earn a reward larger than $100 for achieving a weight-loss goal was probably a strong motivator. Two factors would have augmented this motivation. First, persons are often overly optimistic about their abilities relative to others and, thus, may have expected greater success, and a larger reward, than fellow group members. Second, expectation of a larger reward would have been reinforced because most group members did not meet their weight-loss goals in most months, leaving a larger reward for those who did meet goals. 

Further research exploring the optimal design of incentive programs is all but inevitable. The Affordable Care Act—health care reform—encourages employers to increase their use of such programs, and large employers will undoubtedly want to study the most cost-effective methods for incentivizing their employees to get and stay healthy.

Kullgren sees the study's findings as a starting point for further such research, noting that incentive programs could well address health issues other than weight loss. "The broader point here about group incentives lends itself to a wide variety of future studies," he says. "For the patient, the way that incentives are designed and delivered is very important. So we have a lot of important questions to answer about how exactly to structure programs to get the best results. Our study begins to answer some of those questions, but it also creates many more questions that we need answers to."

Read the study.
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