My Girlfriend hates that Im fat..

Ditch her. She's out for herself. Then ditch the weight and you'll feel like a whole new man.

It's one thing for her to worry about your health - my husband is over weight and I do worry about this. I don't want me and the kids to lose him earlier than we have to. But this woman is trying to change you into "her dream man"? And she "only" stays because you're a good man? Sounds like she expects you to be grateful and thinks she's better than you. Fuck her. You can do better.