Roxane Gay
When Roxane was 12 years old she was gang raped. From being a normal sized teenager with a somewhat normal life, she soon become obese, which then led to morbidly obese before she finally became super morbidly obese. Her parents and herself alike could try their best to fight her weight gain - and she would loose weight. However, that was not the problem alone, the root of her steadily raising weight was in her emotional trauma, and not in the food.
Roxane Gay's body
Roxane Gay is not her body, but her body is a symptom of who she is. In the book, her body is one of the main characters, a person detached from Roxane herself. It is painfully clear that Roxane Gay's life led her to become the person she is, with the body she has. The whole book is a portrayal of how her body isn't a reflection of her, though at the same time it is.
Her body is obese. Super morbidly obese. And it affects the way people look at her, the way they treat her and the way they act around her. Her body was abused as a child, and her body is a response, of the trauma she went through and never truly got to deal with.