This book sheds new light on the political battle to define and construct obesity as a policy issue. Through a rich analysis of the debates in Australia and the UK, it develops a nuanced analysis of the competing narratives that actors rely on to make sense of and argue about this issue, and documents how and to what effect they draw on scientific evidence to support their accounts. The real 'war on obesity', it demonstrates, has always been over the meaning and nature of this public health crisis. This insightful work will interest scholars of interpretive policy studies, critical public health and science and technology studies.