You can't change someone you are with to make them into who you want. Move on and find someone who is what you want. If she does change shes going to leave you anyways because shell be feeling so good about herself that shell think she can do better than you even if she cant. But I have seen in several times in the past where someone I know pushes their significant other to clean up their life, get in shape etc and when the person does improve their life they think they can improve their boy/girlfriend and they will also have some resentment for being forced to change