Overweight and obesity are an accepted cause of numerous metabolic disor-ders. The obvious strategies for prevention and therapy of increased fat body mass (reduction of energy intake, increase of physical activity) fail in most cases, especially with respect to their sustainability. The lack of success of programs developed so far for prevention and therapy of obesity suggests the existence of poorly-understood regulatory mechanisms leading to the imbalance between energy uptake and energy expenditure. Besides physiological factors,such as dysregulated levels of hunger-controlling or satiation-mediating hormones, the composition of the intestinal flora and synthetic compounds with hormone-like activity have been suggested as triggers of the development of obesity. Along with biological and metabolic parameters, scientists have focused more and more on psychological and sociological factors in the development of a strategy for the prevention of obesity. Important factors in this context are the motivation and ability to self-regulation and aspects of the socio-cultural context. Consequently, the real challenge in reducing the prevalence of obesity is not only the identification of relevant parameters but also the assessment of proportionality of these factors. To achieve this goal, borders of disciplines dealing with obesity development (nutrition, medicine, kinematics, psychology, sociology) need to be overcome. Common models must be developed that facilitate the assessment of both the importance of single factors and their relationship to each other.