johnxyz wrote
Dieters are the most boring people in the world. They have to discuss every little thing they eat, don't eat, could have eaten, etc. She does not have to bring this up constantly when she knows you are against it. She is not being supportive of you either.
Yes, because one guy's boner is more deserving of support than the health of someone he loves.
Also, doctors are just as fat phobic as everyone else. Losing weight is not healthy.

I'm a feeder, but surely you can't be serious about this one. The fact that the OP noted that her health has improved since she's lost weight kind of disproves your statement here.
Since most people regain more than what they weighed, encouraging patients to start the yoyo dieting and roller coaster ride where usually the person weighs more in the is NOT healthy.
Agreed on the yo-yo dieting and such; but she's lost 70 pounds and seems to be intent on losing more. This isn't following some 30-pound fad diet- from what the OP is saying, she's changing her lifestyle. That sort of change keeps the weight off better than just cutting down on carbs or whatever.
There are no diseases that only fat people get, so there is no guarantee that even if she lost weight, she would solve any medical problems. If she has any issues they should be addressed by treatment, not a diet.
There might not be many ailments exclusive to fat people, but being fat can put someone at a higher risk of health issues and serious complications.
In any case, no matter who is right and wrong, I think you two can never be happy together right now. I would find someone else. By the time that is ready to end, chances are your current girlfriend will be bigger than she ever was. And maybe realize that dieting is useless.
And with this you've just shown again that you're a douche. I would sincerely hope that a guy wouldn't get picked up again by a woman he dumped just because she wasn't fat enough.