[Burden of obesity: from epidemic to costs].

Nowadays, we count over 300 million obese in the world and this figure could double in twenty years. In industrialised countries, the prevalence of obesity is between 15 and 30%. In 2002, one third of the Swiss population suffers from excess body weight and obesity represents 7.7%. An increase of daily energy intake and a reduction of physical activity are the main causes. In 2001, the global costs induced by obesity and excess body weight in Switzerland reached CHF 2,690 billion. 98.4% of costs are due to obesity complications and only 1.6% are linked to the treatment of obesity without complication. Further prevention could be done with children and within a poor socio-economic population.