Addressing the question of how medicine should engage with people who consider their clinical disease condition to be importantly constitutive of their identity, this article focuses on one group—advocates for the fat acceptance (FA) or body positivity movement in American society. Drawing on philosophical analysis, I try to show that FA and physician communities represent different traditions within the larger culture and that whether obesity should be considered a disease is a culture battle. I argue that diseases (medical) and illnesses (...) (cultural) are 2 different designations of clinical symptoms and that both disease and illness designations can change over time or be uncertain. (shrink)