This study assesses the impact of an eating disorders universal preventive program on a representative sample of Spanish adolescents in the area of Barcelona, Spain. 323 adolescent girls were assigned to three experimental conditions: complete intervention, partial intervention, and non-treatment. The program obtained a significant change in reducing the influences of the aesthetic body ideal and in improving the knowledge of nutrition. Nevertheless, attained post-treatment changes dissipate at the 6 month follow-up. In our opinion, the lack of lasting effects should be attributed to a series of considerations such as format, tests not validated for this age, or insufficient research.