Mental health problems implicitly and particularly pose questions about the tensions of the social world. Anorexia nervosa and bulimia, two eating behaviour disorders, are conceptualised in this article as exposing the social tensions particularly affecting young girls, and more frequently those from the middle and more affluent social classes. Why are these three structuring characteristics of social position female sex, comfortable social milieu, and "youth" interpretable in terms of social relations, and are they thus closely intertwined in these syndromes? Their configuration in eating disorders is atypical among health inequalities that more usually affect men and those from the poorer and older groups in the population. The sociological examination of these behavioural disorders shows that their foundations are not based on excessive conformity with the norms and values that would be expected of girls of the affluent classes but have more to do with a "pathological use" of the norms of excellence in response to the tensions encountered at this age.