 Participants are randomly assigned to either join a web-based risk-reduction program or receive no intervention. The 9-week risk-reduction program focuses on reducing body image and weightshape concerns, identifying the risks of eating disorders, and increasing healthy weight regulation practices. The program includes weekly readings, writing assignments, and participation in a moderated electronic discussion group. Changes in body mass index BMI and the occurrence of major stressors and psychiatric events are assessed to determine their impact on the incidence of eating disorders. One-year incidence of eating disorders is determined by a diagnostic interview, and follow up may continue for up to 2.5 years. 