I have the same weigh and the same size as your girlfirend, so I think I can understand her and I can understand you. Has she ever thought about changing her way of life? Not in a diet or sports way but more in a change of job or town? I've always had weigh problem and 4 years ago I had to move for my job. I quit my friends and family and start a new life. 6 weeks after I had lost 20 pounds without any diet or changing my habits. The thing was that I was not happy home and that I was just compensating by eating a lot. Maybe you can think about a change of air during 2-3 weeks and see if there is a positive effect on her