My Sister Really Isn't This Stupid

After my sister left for college she changed. She used to be this shy but smart girl. Now she's one of these girls with stupid words written on the butt of her pants and acting like an idiot. Really, like an idiot. She hides how intelligent she is and acts like her greatest ambition in the world is to lose five more pounds. I know she had a hard time in high school, not feeling like she fit in, never getting much attention from guys. I tried to tell her that guys that age are stupid, that things would change when she got into the real world, that she would be appreciated for who she is. But I don't know, maybe she gave up when she saw college is a lot like high school. I don't like this version of her and we barely talk anymore. Do you have a book that will fix her?