Decades of obesity research have yielded no generally accepted strategy for safe and lasting weight loss. In spite of the importance given to it, obesity seems to be spreading like a virus. Is there really an epidemic of obesity? This survey looks at studies of the last 10 years from Germany, Europe, and worldwide and compares them with older data.Currently 32.9% of US adults and 13% of US children are obese; in Europe 15.7% of adults are obese and 4% of children and adolescents; in Germany 22.9% of adults are obese, while the figure is 6.3% for children and adolescents. Obviously there are characteristic differences in the worldwide distribution: obesity is more prevalent among women and also in lower social classes or among migrants. Every seventh non-Hispanic black woman in the US has a body mass index of over 40 kg/m(2) (morbid obesity). Obesity is increasing worldwide, especially among children. Morbid obesity is growing twice as fast as diabetes mellitus prevalence and will overtake it.In summary, obesity has developed from a secondary issue to a major national and international epidemic. In the near future, costs of prevention and treatment of obesity and its complications can no longer be covered by the health system. This explains why obesity is politically not recognized as a chronic illness.