i'm shallow hal without any bullshit hypnosis... lol... but pretty much what neooutlaw said. I run, play sports, don't smoke, only drink recreationally (lol...), and generally keep myself in good, fit shape. I'm not ugly (nor do I personally find myself necessarily ATTRACTIVE... but having had gf's obviously SOMEONE disagrees with me..lol) and therefore I have a certain opinion of how the person I am dating/spending the rest of my life with is going to have to look. You can't have a "real" sexual relationship with someone you are not physically attracted to. I can be the BEST of FRIENDS with a large obese person...but sexually its a complete no-go.
Now..its a different story if the girl got fat after say... having a few kids or something... because thats bullshit to divorce someone because of something like that... unless there are lots of other issues too. I'd STAY with a chick if she GOT fat after some amount of time (but the girls I've tended to be with are your typical cali-chicks... white, blond, nice on the inside but a bitch on the outside (or vice versa..lol)).
But everyone has thier own standards and generally those standards can and SHOULD be related to how your treat your own body. If you don't mind that YOU are overweight... than I don't REALLY believe you should hold it against someone else.... which is why I STAY in shape and so I kinda expect the same of whomever chick I'm taking a shower with...lol.