[Obesity: the epidemic of the new millennium between genetics and environment]

Obesity is a complex epidemic disease, resulting from the interaction of predisposing genetic factors and causal environmental and behavioral factors. The latter are primarily responsible for the recent epidemic. In recent years, genome-wide association studies have identified genetic variants associated with the development of obesity. Though discoveries in this field may hopefully lead to a personalized approach to the prevention and management of obesity, so far lifestyle changes remain the only effective tool. It is extremely urgent to intervene because obesity-related diseases are increasingly encountered in young people and children.