What's odd about this cover?

Now.

I'm not saying that there's a thing wrong with the book itself -- I haven't read it, as it comes out in November.

All I have to go on is the description of the three protagonists at Amazon:

Patient #1: Female, age 16, 5'4", 288 lbs.
Thrust into size-zero suburban hell by remarried liposuctioned mom. Hates new school and skinny boy-toy stepsister. Body size exceeded only by her big mouth.
Patient #2: Male, age 16, 6'2", 335 lbs.
All-star football player, but if he gets “girl surgery,” as his dad calls it, he’ll probably get benched.  Has moobies—male boobies. Forget about losing his V-card—he’s never even been kissed.
Patient #3: Female, age 15, 5'6", 278 lbs.
Morbidly obese and morbid, living alone with severely depressed mother who won’t leave her bed.  Best and only friend is another patient, whose dark secret threatens everything Patient #3 believes about life.

Now, granted, the three characters have been "admitted into exclusive weight-loss surgery trial", so it's clearly a story that deals with weight-loss, but...  I dunno.  Or am I being too picky/overly sensitive/looking for problems where there are none?