my friend....

um are you sure she isn't anorexic? like if she doesn't eat because she thinks she is fat then isn't that anorexic ?

um...well i think if its for attention which no offense, thats what it could seem like, but she might be saying this so you worry about her or something...i dunno.
but even if you think it is for attention you should have a really serious conversation with her...see what its all about because you cant start getting stressed out if its nothing but you cant leave it if its something if that makes sense?
xxx

Just ask her if she's not eating for attention or because she's trying to lose weight or what. I went through the same thing and I'm kind of going through it now, I see myself as fat (long story) so I'm not eating much and she may be doing it just for attention, but she may not. Try to find out, but don't push it.