Come to think of it, Isabelle Lucas would have also been a FANTASTIC choice.
Her or Camilla Belle like you guys mentioned before would have been so, so much better.
Incidentally: on one hand, I sort of see why Jennifer Lawrence is making a stand. Like, "here's my body, I'm not going to change it, this will show girls with similar bodies that it's okay to have a body like mine, too". Alright, fine. It's not the type of body I personally would prefer or admire, but I'm for representing diversity in that regard (within limitations, because I still won't support showcasing pro-obese body types). BUT. All that said, this is NOT the movie to do this in. I think the beef most people have is that it just plain doesn't suit the character. And her staunch refusal to lose weight to fit the character and role is what annoys me. Natalie Portman and Mila Kunis lost significant weight for Black Swan, not necessarily because they like that body weight, but because it would be unrealistic to have anything but uber-thin ballerinas. Renee Zellweger gained weight multiple times to play Bridget Jones, because her being chubby is such a central feature of that singular character. See: Christian Bale in the Machinist. See: Charlize Theron in Monster. Actors do it all the time, it's part of their job. I think it was silly of Jennifer Lawrence to try to make a point with this particular movie, because again, she simply has the wrong body type for this particular role. I mean, it's partly her fault, but also, what was the casting director thinking?
I've been watching a lot of Lost lately, which takes place on an island in the middle of the ocean, where, for the first season and a half, the entire cast only has access to fruits they forage, fish they catch and boars they hunt. Every female cast member in the show is represented as skinny-to-thin, there's lots of visible xylophones everywhere, no one has excess fat, everyone has deep tans, everyone basically looks like I would expect them too if they didn't have regular access to food and were in the bright, tropical sun, day in and day out. It's realistic, and it suits the theme.
But that may because he is one of my favorite actors ever. Liam Hemsworth is a babe 
this is sooo true!
