Like, I just was thinking about how lots of pet species will just eat as much food as you give them to the point of making themselves sick, and keeping them at a healthy weight requires not giving them access to too much food. Obviously some humans have problems with this, but imagine how bad things would be if everyone were basically psychologically incapable of not eating food when we had access to it even when we’d had enough, given our dramatically higher access to food due to agriculture.
My husband is like that, too. Something I tell him is to not have seconds (as in, a second plate of food) for 10 minutes. If he’s still hungry, then he can eat. (I say the same thing about sleep. I tell him to just lay there for 10 minutes and see if he can sleep) usually works. Sometimes it doesnt. You could give it a try if you like