Husband remarked on this a few months after I started Primal: that I was often leaving food on my plate. I'd had enough, so I stopped. Obvious - except I'd never done that before in all the time he'd known me.
Interesting thing is that after eating all the leftover chicken plus vegetables I wanted, I still had to slap down an impulse to go find some sweet crap. The desire to eat sweet stuff seems completely independent of hunger.