Résumé
This paper compares distributions of Body Mass Index (BMI) among men and women in France, the US and the UK on the basis of a new normative criterion. Comparing distributions of BMI from a normative standpoint is conceptually challenging because of the ordinal nature of the variable. Our normative criterion is well-suited to handle this issue. It coincides with the possibility of moving from the dominated distribution to the dominating one by a finite sequence of Hammond transfers and/or elementary efficiency gains. An additional difficulty with BMI is that it is not monotonically increasing (or decreasing) with health or well-being. We therefore perform our analysis by considering all health-consistent rankings of BMI values. Our empirical results are striking. For a large class of these rankings of BMI values, it is shown that the distribution of BMI in France has worsened on the period 2008-2010 for both men and women according to first order dominance. It is also shown that for most welfare rankings of BMI values, the distribution of BMI is worse in every period in the female population than in the male one in all three countries.