Drawing on research investigating the impact of health imperatives around obesity, diet and exercise on the actions of teachers and pupils in schools, this paper offers a reflexive account of the relationships between the "noise" of obesity discourse in the public domain, policies forged to tackle health issues and the realities of teaching in schools. Our analyses suggest that intersections of bio-policies, body pedagogies and human agents forge assemblages of meaning that frame and regulate but "cannot" determine either teachers' or young people's lives. Teachers and pupils experience the capriciousness of policies as they flow through specific school contexts and intersect with "local" institutional cultures, expectations and interests. We suggest that Basil Bernstein's concepts and poststructural social theory prove useful when addressing how the aforementioned processes are "emplaced," "enacted" and "embodied." (Contains 2 notes.)