I have to disagree with Zimmer; I doubt this is as simple as a phase. Once a girl gets that thought into her head, it's very hard to get it back out again. My wife was overweight as a girl, taunted all throughout school, and even after she got her weight under control through daily exercise, she still continued on with that mindset that she was fat, and as a result, unattractive. Do NOT let your daughter fall prey to this; it can literally affect her for the rest of her life!!