My purpose in this paper is to consider the relationship between, on the one hand, critical social science and, on the other hand, existing and emerging sciences of the body. Taking my lead from the sociologist, Steve Fuller, I discuss the ways in which some social scientists, both within and outside physical education and sport, have engaged with the idea of an ‘obesity epidemic’, generally falling between the distant poles of naïve acceptance and ideological rejection. Using new and emerging forms of biological determinism as a second example, I describe the colonising tendencies of particular medical and biological sciences, such that robustly social understandings of the body and less instrumental approaches to physical education are, i...