Sadly, I know a girl in college who's headed down that path.  She's insisting that she's going to get fit, yet she keeps pigging out (because it's HARD to stick to a calorie limit!) and still hasn't looked at the gym.  It's a shame because she's still a healthy weight, has a cute face and amazing boobs (most of her unnecessary weight is in her thighs).  I'm praying she'll get her shit together before she falls off the cliff, but I'm not hopeful.