the girl on the right IS fat. no two ways about it. its a fucking photo shoot. which means it has been air brushed and made up to all hell. you see that girl in real life, she will have creases everywhere from when she sits down and her fat flops over itself, probably has the cellulite arse etc. if she is 5'8 her weight would be 80-90 kgs which = overweight = fat.
whatever floats your boat with respect to chicks, but if you want to tell me she has a healthy physique with an ideal weight, then you are just kidding yourself.
*edit* also checked the photo again, because someone mentioned that 'the angle didn't do her justice' or something - are you kidding? notice the following:
1. she is facially side on to the camera, but her belly is facing the camera so as to hide the fact that it sticks out
2. she is wearing black (as all of them are, but still valid) because that is the most thinning colour / shade
3. her legs cross over each other and are twisted, so you can't see both in total width
.... and they are just things i noticed as an amateur. make no mistake about it, its all geared to make her look as 'not fat' as possible, such that FHM could prove the point they wanted to make.