Aim: The issue of excess weight and obesity among our young people is currently under discussion as one of the most serious problems in public health. Extensive work has been done to analyse the problem, to indicate the drivers, and to create prevention programmes. Much research remains to be done in the field of modelling the complex impact network of familial and societal influences on juvenile obesity. To achieve this, the forecasts and results issued by the various disciplines must be integrated. The aim of our work has been to create a causal-loop model of obesity in socially disadvantaged children and adolescents that allows qualitative simulation, group-specific risk assessment, as well as the identification of key factors for prevention. Subjects and Methods: The model was created in cooperation with 18 experts from the field of obesity research. The participants were drawn from eight different disciplines including medicine, sociology, and prevention. Four expert workshops pinpointed 43 main obesity drivers at the individual, familial, and societal level; these were rated according to their causal interdependence and impact. The computer-based method of cross-impact balance analysis was used to evaluate the model and to produce risk profiles for different societal and individual context situations. Results: The model analysis reveals that there is no one single key factor that can be expected to act as an effective prevention factor for every scenario. Instead, both the risks and the effectiveness of prevention measures depend strongly on the specific characteristics of an individual's own environment. Conclusion: Consequently, it would appear sensible to approach the design of prevention programmes from a groupspecific, multi-factor and multi-level perspective. © Springer-Verlag 2012.
