It is okay to be fat. This is the basic premise of fat activism, a social movement that has existed in Canada since the early 1970s. In Being Fat, Jenny Ellison focuses on the earliest strands of the Canadian movement, which emerged around 1977 and ended around 1997 with the emergence of defiant performance artists Pretty, Porky, and Pissed Off. This twenty-year window loosely correlates with the rise of "second-wave" feminist organizing and thinking in the country. Fat activists were wrestling with issues other feminists of the era were debating: femininity, sexuality, and health.

While united by the idea that it is okay to be fat, the movement has taken many different forms. Fat "activism" and the "movement" encompassed a variety of activities. It included groups that held regular meetings and published newsletters, organized events, and elected an executive. Being Fat explores activities like fashion design, self-help groups, plus-size modelling, and dance under the umbrella of fat activism, undertaken in the name of empowering fat women. Together, these activities show that self-identified fat women took up feminist ideas of liberation and applied them to their lives. Their personal experiences became the basis of a powerful movement to challenge beauty and bodily norms.