I struggle too with overeating.
When people keep doing something that seems negative and "easy to fix" usually there is some kind of payoff, that is why they can't stop.
Being fat keeps people from noticing me. I am very shy. I used to be very slim and very attractive but I hated the attention. When I had to go out in the world, I started overeating and getting fat. That is the payoff. It keeps people away and makes me feel safe.
You probably can't stop overeating and "being fat" because there is some kind of pay off.
I want to see if I can get over this with fasting too. If I face the feelings and thoughts that start going through my mind when I get the urge to overeat while fasting. If I can defeat those feelings and thoughts, then maybe I can stop overeating.