Effectiveness Trial of a Dissonance-Based Obesity Prevention Program

Obesity is a major US public health problem. Few obesity prevention programs have reduced
risk for weight gain over follow-up and those that have are very intensive, making
dissemination difficult and costly. A brief 3-hr selective prevention program (Healthy
Weight) targeting young adults with body dissatisfaction involving participant-driven healthy
dietary and physical activity lifestyle changes significantly reduced increases in body mass
index (BMI) and obesity onset relative to alternative interventions and assessment-only
controls through 3-yr follow-up, though effects were small in magnitude. To enhance efficacy,
the investigators added dissonance-inducing activities regarding unhealthy dietary and
activity practices, drawing from a highly efficacious dissonance-based eating disorder
prevention program. A pilot trial found that this new Project Health intervention
significantly reduced increases in BMI relative to both the Healthy Weight intervention and
an educational brochure condition from pre to post. The investigators propose to conduct a
rigorous multisite effectiveness trial that will test whether adding the dissonance-induction
elements to the originally Healthy Weight intervention improves weight gain prevention
effects. 360 college students at risk for future weight by virtue of their age and weight
concerns will be randomized one of three conditions: (1) a refined 6-hr group-based
dissonance-based Project Health, (2) a 6-hr group-based Healthy Weight intervention, or (3) a
psychoeducational video ("Weight of the World") condition. Participants will complete
assessments of % body fat, mediators (including objectively measured physical activity),
moderators, and other outcomes at pre, post, and 6, 12, and 24 month follow-ups.