We suggest that recent concerns about young people’s excess body weight have generally been treated quite separately to longer standing concerns about young people (particularly, young women) and eating disorders. The few papers that have addressed this connection directly have focused on how practices motivated by the obesity discourse have had damaging consequences for the ways young women have come to understand and act on their bodies. The research described in this paper, however, makes a different point. It demonstrates how one teacher struggles to negotiate the different and often contradictory meanings about the body and young women’s health, in a context where explicit teaching about eating disorders and body image is formally endorsed and legislated through the State health and physical education (HPE) syllabus. The interview material and classroom exchanges described in the paper are from a project that examined the implementation of a sociocultural perspective as a curriculum change in HPE. The case presented here took place in a girls’ private school, where an accomplished female HPE head teacher developed and taught a unit of work focused on food and nutrition to a class of 15- and 16-year-old female students. Our analysis suggests that, within this particular gendered and classed setting, the teacher understood the students in her class as being at greater risk of developing eating disorders than of becoming obese. However, despite the apparent ‘risk’ presented by eating disorders, the investments both students and the teacher had in their own bodies as the slim ideal, meant that learning and teaching about how to avoid being fat continued to be paramount. We suggest further research is required to understand how teachers negotiate the intersection of obesity and eating disorders in the formal curriculum and across different social and cultural contexts, and to draw on this in advising teachers in relation to future practice.