Since overweight and obesity have been framed as one of the main contemporary health challenges in industrialized countries, it has become a matter of public health efforts. While the belief that obese individuals are personally responsible for their body weight prevails in public opinion, evidence-based health science widely acknowledges that obesity is significantly influenced by socio-economic factors and thus that prevention requires structural changes. This constellation bears the chance of politicizing an issue formerly conceived of as private which really is (...) dependent on societal contingencies, such as the particular availability of food. Reflecting on the prevention of obesity from an ethical point of view, therefore, requires an elaborate concept of political responsibility. The core thesis of this paper is that existing approaches within the field of obesity ethics fall short in reasonably grasping the political dimensions at play, due to the prevailing individualistic understanding of responsibility. Drawing upon Iris Marion Young’s concept of political responsibility, I propose an alternative approach that emphasizes the structural determinants of obesity. By arguing this way, obesity prevention comes into view as a public endeavor that involves public discourse as well as shared action. Political responsibility then cannot be discharged merely by intrusive governmental action nor by individuals on their own, but should be considered as a task all of us share. As I will sketch in the last part of the paper, this includes contesting discourses on interpretations of need. Thereby, the paper contributes to recognizing obesity as a social instead of an individual problem. (shrink)