[Definition and epidemiology of massive obesity]

Massive obesity is defined by a body mass index [weight (kg)/height (m)2] greater than 40. It corresponds to an increase in mortality ratio. Its frequency differs among countries and its incidence is important in USA (13 million subjects), Finland, and South Africa. Obesity is now a serious, emerging problem in developing countries. Frequency of obesity is influenced by age, sex, race and has increased during the last 30 years. Importance of heredity has been highlighted. Recently an increase in superobesity in childhood has been observed, especially in the United States. Finally, besides people with stable obesity throughout their life, there are subjects with weight cycling. These subjects have higher cardio-vascular risks than the others.