This article is a version of the Ryley-Jeffs Memorial Lecture, delivered on 8 June 2018. It discusses weight bias and the intersections with homophobia, racism, and misogyny, and how these impact health. While the dominant discourse attests that people can lose weight and keep it off, evidence informs us that maintenance of weight loss is unlikely. Using a flawed epistemological framework, obesity has been declared a disease, and weight bias been perpetuated. Weight bias is pervasive, both in the general public and amongst health professionals, often using inappropriate tools to assess the impact of weight on health. This contributes to overlooking the life circumstances that truly cause morbidity: social determinants of health such as income, social connectedness and isolation, adverse childhood experiences, and cultural erasure. A variety of tools dietitians can use to appropriately assess health risk are provided, along with examples of actions that can be taken to reduce weight bias. Dietitians who are leading the profession in taking action against weight bias and stigma are profiled.