Online commitment contracts for weight loss

Background: Commitment contracts are behavioral economic tools where individuals make contracts with themselves to achieve a goal. Individuals can put down money (“stakes”) to incentivize themselves to achieve the goal; if they do not complete the goal, they lose the money. The participant can designate lost stakes to an organization that s/he likes (i.e. charity), one that s/he dislikes (i.e. “anti-charity”), or to a friend. Our objective was to determine what components of commitment contracts for weight loss are associated with the largest percent decrease in weight. Methods: We obtained data on commitment contracts (n=5024 individuals) for weight loss from stickK.com, a company that allows individuals to create online commitment contracts. Individuals specified their own weight loss goal and self-reported their weight weekly. Our primary outcome was the percent weight loss. Results: The average age of the individuals was 38.6, with 70% being female. The median duration of the contracts was 15 weeks. On average, participants reported losing 5.2% of body weight. Participants who put down anti-charity stakes lost 7.7% of body weight, compared to those who put down charity stakes (6.8%), those who put stakes towards a friend (6.3%), and those who did not put down stakes (3.4%). All, except the charity and friend groups, were significantly different from each other. We will present full regressions that model the factors associated with weight loss. Conclusions: Commitment contracts may be effective tools to assist individuals in losing weight. Adding a monetary incentive may increase the amount of weight loss.