Why do women hate fat guys?

This is a genuine question. I am a fat guy, and I am dating a woman who is very insecure about my weight and she says that I should be more healthy and I should do some sport and stop eating so much, and I said "hey I am healthy I just have some weight and I do some sport, and I eat what I want". And she says that I should be more healthy and I should stop being so fat, and she said "you should go to the gym and be healthier, and you should eat more vegetables, and fruits, and you should stop eating chips and candy, and junk food, and all of these unhealthy foods", and I said "hey I am healthy, and I don't need to be skinny and thin, and I can eat whatever I want, and I can eat junk food and unhealthy foods, and I can watch whatever I want, and do whatever I want". And she said "you are not healthy, you are fat and you should be thinner and healthier, and you should stop eating junk food and stop watching porn, and you should be more mature and not be so immature". And I said "hey I am healthy, and I don't need to be skinny and thin, and I can eat whatever I want, and I can watch whatever I want, and do whatever I want, and I don't need to be healthier, and I don't need to stop eating junk food, and I don't need to stop watching porn, and I don't need to be more mature, and I am not immature, and I am mature".