Eating disorders (ED) and body image problems are associated with impaired well-being, adaptability, and individual and collective economy. In addition, they involve considerable suffering. It is estimated that such problems are increasing in recent years. Consequently, it is important to carry out effective prevention programs, and for this it is important to know the associated risk and protective factors. However, the scientific literature tends to focus on the first type. Objectives: This thesis has two objectives. The first seeks to evaluate the short-, medium- and long-term effectiveness of a prevention program. The second seeks to identify the relationship between various risk and protective factors in the development of symptoms of eating disorders. Methods: Both studies were conducted with a sample of 14-year-old girls and boys. The first study consisted of 308 students and the second 226 students. The distribution of sexes was girls: 45.8 / 49.1% and boys 54.22 / 50.9%. The first study was analyzed using a mixed factorial design, 2 (condition) × 3 (time: post-test and follow-ups of 6 and 12 months). The second study was analyzed using multigroup structural equation modeling. The variables analyzed were body satisfaction (QÜIC), self-esteem (RSES), emotional intelligence (TMMS), perfectionism (CAPS), internalization of the aesthetic ideals (SATAQ-4), symptomatology of the ED (EAT-26) and Body Mass Index (BMI) anthropometric measurements. Other sociodemographic measures such as eating habits and physical activity were also evaluated. Results: In the first study, participants in the experimental group showed significantly higher scores on body satisfaction, self-esteem, emotional intelligence, and lower scores on self-centered perfectionism and internalization of the ideals of thinness and musculature with respect to the control group in post-intervention measures and in both follow-ups. In the second study, there were differences concerning gender. In both genders, self-esteem and body satisfaction acted as protective factors while the internalization of aesthetic ideals was presented as a risk factor. Conclusions: Universal and ecological programs implemented in both genders could be effective in reducing risk factors and / or maximizing protective factors and reducing body image problems and eating disorders. Optimizing protective factors in the context of health prevention and promotion programs and in the treatment of EDs and their evaluation could provide additional benefits. Based on the results, we recommend more research regarding suppressing negative emotions, the role of adaptive perfectionism, and the current positive body movement.