The Designated Ugly Fat Friend by Kody Keplinger 277 pages

This is a fantasy. Not a dragon and knight kind of fantasy, but the ugly girl catches the school hottie. 17 year old Bianca hangs with two friends who attract all the guys when they go out. Bianca is tired of being the designated driver watching from the sidelines. She hooks up (literally) with Wesley who has the reputation of being a "man-slut". He coins her with the nickname of "the Duff" (see title). Although her feelings are hurt, she can't seem to keep her hands off of him and he becomes her distraction when other pieces of her life are falling apart. Could this happen in real life? She has serious self-esteem problems and he just doesn't seem to be the enlightened kind of guy to make the effort.