In in this time of national obesity, The Fat Girl remains an archetype in American Literature. The latest rendition of this is Judith Moore's "Fat Girl." It's a wonderful tale of self-loathing and torment from society. Before that, the best in this genre was Wally Lamb's "She Came Undone."
The Fat Girl genre can only thrive in America because we are a nation still stuck in the illusion of self-improvement and non-acceptance of anything sort of perfection. Whatever is wrong can be fixed, with enough determination and imagination. Therefore, The Fat Girl represents either a failure of this ethos or, worse, perverse rebellion. As such, The Fat Girl must not be left alone. It demands constant notice and due punishment. That's our national duty.
The Fat Girl, of course, has nothing to do with weight. It's a mindset: I am less-than because of weight. Laura Bush, although usually overweight, is no The Fat Girl. She has too much of a sense of self. The same goes for her mother-in-law.
Interesting to observe, The Fat Boy is emerging, but the archetype hasn't really made it into art yet. It's still at the developmental stage of being a pest in 12-step programs focused on weight, gay hangouts, gyms, and family dinners at which it draws the attention it craves by not eating enough or eating way too much.