Scientific evidence supports an interactive model of biopsychosocial influences on the etiology of eating disorders. New genome-wide association studies suggest underlying metabolic dysregulation in anorexia nervosa. Among the psychological factors, body dissatisfaction (IC) is the most consistent predictor, mainly in females. Low self-esteem, negative affect and internalization of the ideal of thinness predict IC. Certain personality traits and other individual factors such as a high body mass index, emotional problems and some metabolic and digestive diseases, social factors such as some sporting or professional activities focused on body shape pressure, characteristics of the family environment, and social and peer group pressures to be thin, currently mediated by the use/abuse of social networks, act as risk factors for ED. Most prevention programs target adolescent girls in secondary education and young people. Interventions at an early age, in adults and in men are scarce. Successful programs focused on one or more risk factors, based on cognitive or behavioral approaches, include content on healthy eating or nutrition, media literacy, sociocultural pressures, and body acceptance or body satisfaction. They incorporate new technologies and are interactive. More research and innovative prevention programs for eating disorders in young children, adults and men are in need.