Financial Incentives for Maintenance of Weight Loss

Study participants will be obese volunteers recruited from a major community-based weight
loss program (Weight Watchers), who have lost at least 5kg during the 4-6 months prior to
enrolling in the study. Among these participants, the following will be assessed: 1. The
effectiveness of a daily lottery-based financial incentive, relative to the control group, on
weight loss and weight maintenance; 2. The effectiveness of a direct payment incentive,
relative to the control group, on maintenance of weight loss; 3. Assess the comparative
effectiveness of lottery-based and direct payment financial incentives on weight loss and
maintenance; 4. The degree to which weight loss is maintained in the intervention groups
relative to usual care during the 6 months following cessation of the intervention will also
be determined.

During Phase I, incentives will be provided to some study participants (direct payment and
lottery arm) for the first 6 months and subjects will be followed for 6 more months to
examine effects following cessation of incentives.

Inclusion Criteria:

- Adults age 30-80

- BMI between 30 and 45 prior to starting Weight Watchers

- Have a documented weight loss of at least 5kg in the past 4-6 months before enrolling

- Stable health

Exclusion Criteria:

- Substance abuse

- Bulimia nervosa or related behaviors

- Pregnancy or breast feeding

- Medical contraindications to counseling about diet, physical activity, or weight
reduction

- Unstable mental illness

- Screen positive for pathological gambling on the basis of the 10 item DSM-IV criteria
(excluded if meets 5 or more criteria)

- Individuals unable to read consent forms or fill out surveys in English