The Impact of Modest Financial Incentives in Promoting Sustained Weight Loss: A Group Randomized Trial

Presenter: Eric A. Finkelstein, Centers for Disease Control and Prevention

Abstract

Objectives: To test whether modest financial incentives can effectively promote increased weight loss when used in combination with an established web-based weight loss program.

Methods: We conducted a group randomzed trial in which overweight/obese employees at 16 community colleges in North Carolina were randomized into 1) a control arm, 2) a web-based weight loss program (web), and 3) a web-based weight loss program plus a modest payment of $5 for each additional percent of weight loss (web plus incentive) from baseline at 3, 6, and 12 month weigh-ins. 965 employees signed up to participate in the study. At baseline, the average weight of participants was 204.5lbs.

Results: Study attrition was just over 30% at 12 months. However, attrition was over 40% in the web arm, compared with roughly 30% in the web plus incetnives arm and 33% in the control group. Using an intent to treat analysis, at each time point, those in the web and web plus incentive arms lost statistically more weight than those in the control group. Although the point estimate showed that the web plus incentive group lost more weight than the web group, these differences were only statistically significant at six months. Similar results were found when comparing the percent of participants who achieved 5% weightloss.

Conclusion: The incentives used in this study were, on average, $2.50 per pound. Although this level of incentive appears to have been too small to generate significantly greater weight loss than those who received WEB only, these modest incentives were successful in minimizing attrition. If incentives are to be successful in encouraging long term sustained weight loss, they are likely going to have to be much larger than those used in this analysis.