Apparently some people don't have this problem, which makes me incredibly envious (or would if I could feel anything).
It's this nagging thought of "JESUS CHRIST YOU'RE GONNA DIE IF YOU DON'T EAT A LOT RIGHT NOW!"
I've experienced it after hard days at work (construction), multi hour lifting, cycling 50km. Same shit every time. Surprisingly, unlike what my dumbass brain says, I don't die if I eat only a little and just go to sleep.
Counting calories didn't work btw. It actually made it worse as my primitive brain would know it's "starving".