I'm not the person you were originally replying to, but hunger cues don't always happen in the stomach.

I was raised as the oldest of seven children. Five of them had been severely neglected in their early years by their biological families. Food was weird in our house. Combine the hierarchy and power struggles of all those kids with food anxiety, and the fact that I picked up a lot of their dysfunctional habits simply by living around them...I ended up with a lot of bizarre feelings about food.

I literally panic when someone takes something off my plate, even as a joke. If I have to share popcorn, I can't shake the feeling that they will get "more" than me. I eat too fast and too much if I don't watch myself. Even when I know I'm not hungry anymore, I have the desire to keep eating. It's very hard to control. I feel upset if people can have food that I can't have, like I'm being cheated or having something taken away from me.

In addition to all of that, I have Asperger's. I put everything in my mouth. I have to monitor myself closely so that I'm not chewing on paper or erasers or pop can tabs. I actually picked up vaping to stop snacking; oftentimes, eating is more about having some sensory stimulation in my mouth [dick joke goes here].

All of these behaviors are hard to reign in all at once. It takes years to cull such odd compulsions and impulses. I still can't share food. I still have to consciously monitor the speed at which I'm eating. I still vape, or I'm liable to be snacking constantly. And like /u/csreid indicated, there's actual, physical pain sometimes. On a moderate-calorie, nutritious diet, I get headaches and pangs and feelings of depression because I feel deprived. I don't know if that's ever going to go away.