I think she is dreadfully unhappy, the image that she is so desperate to portray online is not her reality and she must be painfully aware of this. She doesn't appear to have any friends (I would guess because she's not exactly the kind of girl you'd want to be friends with but the reason why doesn't really matter here), doesn't do anything, has been living with her parents after living it up in London pretending to live the life she wants, her boyfriend doesn't appear to be interested in her at all, she has no actual talents and no personality. All she has is her looks and I guess she's been clinging on to them so hard but look at what it's done to her. I can't believe that picture above in 2016 is even her, she looks absolutely beautiful and now she just looks awful. She is the sort of girl who is genuinely naturally pretty and all the fake crap she's had done has started to ruin her.
I imagine the problem with her weight/potential eating disorder is centred around all of this, of course it's just speculation, but she appears to be the sort of young girl who is soooo desperate to keep up with others that she will do anything to make her life look the way she wants, even if it is fake, and it must begin to get you down when you look into the world and what you see isn't what you want to see.
This is just my thoughts, I hope she does get some help because she sure as hell needs it.