This thesis examines the roots of the representation of fat women in the popularised body positivity movement in recent UK and US culture. Popular critiques of body positivity tend to suggest it is a dilution of the more ‘radical’ fat activist movement of the late twentieth century which has erased fat women from its focus (Dionne 2017; Kessel 2018; Rutter 2017; Severson 2019). However, Cooper (2016) theorised that there are many proxies of fat activism, with body positivity being just one. I examine this bond, and ask: What is the relationship between body positivity and fat activism? What kind of fat body positivity has developed because of fat activist practices? And, what bodies (and people) does fat body positivity celebrate? These questions are relevant to me as a scholar of fat studies, as well as a fat woman affected by the perspectives of body positivity. I therefore navigate the ever-changing body positivity movement and address my questions via a methodology which consciously threads my own fat stories through these knotty questions. I follow the ‘pricking of my thumbs’ (Hennegan 1988) to locate a variety of texts that ‘represent’ fat body positivity. By engaging with my autobiography alongside texts from online magazines, published autobiographies and blogs, I trace a history of fat body positivity from its origins within fat activism. I argue that this narrative centralises around five themes: whiteness, femininity, heterosexuality, health and self-love. In examining these themes (or proxies) of body positivity I uncover significant cultural moments that connect understandings of fat activism and body positivity and identify important absences that ‘haunt’ the movement. I argue that both movements have led to a narrowly-focused acceptable fat body positivity and conclude by offering tentative ways forward for a more liberatory representation of fat bodies.