For 30 years, corpulence (frame 1) has developed differently in France to the States. Even if, these past years, the phenomenon has seen quicker growth in France, obesity can be compared neither by its extent nor by age or gender. On either side of the Atlantic, obesity is linked to social status, particularly women, and though it extended in every social milieu between 1970 and 2000, no real weakening of the part played by social factors in obesity is noticeable. The survey on attitudes to weight, varying according to social categories, shows that the most affected individuals belong to social groups where average corpulence is higher and where attention to weight is lower. Should there not be a preventative public health policy focusing on all middle to lower classes?