One of the main objectives of the National Plan of Prevention is prevention of overweight and obesity. The realization of such plan has been submitted at ASL level mostly to the Food and Nutrition Hygiene Services (SIAN) according to their competences, as well specified by the decree of October 16th 1998, which deals with the collective nutritional prevention and overseeing. In the following sections we present the experiences of some SIANs considered meaningful in order to offer a survey, along the whole country, of what already realised about prevention of the obesity and promotion of correct life styles.