In Germany, the number of overweight children and adolescents is increasing. The increase in the prevalence of obesity shows considerable regional differences. Related to recent German reference data with an expected prevalence of 3%, we find today in some regions a prevalence of 7% in 5- to 6-year-olds and 8% in 13- to 15-year-olds. While the reasons for this development are not fully clear, it may be assumed that the increase in physical inactivity, together with the ready availability of an abundance of high-energy foods are significant contributing factors. A large percentage of children and adolescents suffering from obesity also have considerable co-morbidity. It is to be expected that this will in the future considerably increase the financial burden on public health care and society as a whole. Effective prevention and therapeutic countermeasures are necessary to deal with this problem.