Challenges in the prevention of disordered eating field include moving from efficacy to effectiveness and developing an integrated approach to the prevention of eating and weight-related problems. A previous efficacy trial indicated that a universal disordered eating prevention program, based on the social cognitive model, media literacy educational approach and cognitive dissonance theory, reduced risk factors for disordered eating, but it is unclear whether this program has effects under more real-world conditions. This effectiveness trial tested whether this program has effects when previously trained community providers in an integrated approach to prevention implement the intervention. The research design involved a multi-center non-randomized controlled trial with baseline, post-test and 1-year follow-up measures. The sample included girls in the 8th grade from six schools (n = 152 girls) in a city near Barcelona (intervention group), and from eleven schools (n = 413 girls) in four neighboring towns (control group). The MABIC risk factors of disordered eating were assessed as main outcomes. Girls in the intervention group showed significantly greater reductions in beauty ideal internalization, disordered eating attitudes and weight-related teasing from pretest to 1-year follow-up compared to girls in the control group, suggesting that this program is effective under real-world conditions.