Thesis: The prevalence of obesity has increased over the last decades in the developed countries, especially among the lowest social groups. This thesis explores the social and economic consequences of obesity in different areas. In France, obesity reduces employment probability for women, and the hourly wage for both men and women. Moreover, obese people spend more time in leisure activities, but it has no consequence on common leisure time in couples in which both partners are obese. In the United Kingdom, obese people are less satisfied than non obese people, but this effect could be mitigated if the partner is also obese. Lastly, international data show that corpulence norms are not uniform between and within countries. In particular, corpulence norms are more stringent for women. It may explain why the estimated impacts of corpulence are higher for women.