Adapted from the famous autobiography '' My Mad Fat Teenage Diary '' of Rae Earl', '' My Mad Fat Diary '' tells the story of the life of Rae Earl, a 16-year-old girl with 100 kilos weight.. The content and context of the film is quite narrow, only around Rae and family, and friends of Rae and her weight troubles. But the problem in this is not narrow, short-sighted and superficial at all, although everything is always expressed through the subjective perspective of the main character, Rae.