The intervention program "Obeldicks" was developed for obese children aged 6 to 16 years. This intervention is gender- and age specific. The 12-months intervention is based on nutrition course, behaviour therapy and exercise therapy. The evaluation compromised quality of structure, process and results of the intervention. Primary outcome measure is change of weight status as standard deviation score of BMI. Furthermore, cardiovascular risk factor profile, hormones (e.g. iGF-I, thyroid hormones, vitamin D status)adipocytokines, GI- hormones, intima media thickness are measured prior to and after the one-year intervention. The changes of these hormones and adipocytokines will allow to answer the questions whether the alterations of these hormones are a cause or consequence of overweight. Additionally, a genetic screening is performed to characterize the participants to probably predict response to intervention.