Over the past years health-policy makers, scientists, medical professionals and citizens alike have increasingly engaged with the ''obesity problem'', searching for its origins and how it could best be dealt with. Simultaneously relations between health and ethnicity have become a matter of local and global concern, directing attention to diversity issues also in obesity-related intervention. But introducing such a focus into biomedical research, treatment and prevention might turn out to be quite problematic through re-essentialising differences. Using qualitative social science methods, this project aims at a fine-grained understanding of “diversity practices” in the obesity context, i.e. how diversity is addressed in research, public health programmes and clinical settings (focus: Vienna) and what implications this might have. In order to foster reflexivity on diversity issues related to obesity, the project will further engage in focused discussion and exchange with relevant actors.