The diabetes and obesity epidemics are closely intertwined. International randomized controlled trials demonstrate that, in high-risk individuals, type 2 diabetes can be prevented or at least delayed through lifestyle modification and, to a lesser degree, medication. We explored the relative roles of science, surgery, service delivery, and social policy in preventing diabetes. Although it is clear that there is a role for all, diabetes is a complex problem that demands commitment across a range of government and nongovernment agencies to be effectively controlled. Accordingly, we argue that social policy is the key to achieving and sustaining social and physical environments required to achieve widespread reductions in both the incidence and prevalence of diabetes.