When I was little, I used to believe that there was a compartment that had the exact shape of the food that you ate. (e.g. when we ate hot dogs, there was a compartment shaped exactly like a hot dog that it filled up.). When I would say that I was full, I would say that "there's still the dessert compartment left to fill up!"
A childhood belief about eating

others believed things like this
- I used to believe that as I ate food, I filled up, and that once I filled up completely, I would die. Anon
- I thought i had to chew my food 27 times before i could swallow because Stephanie said it on Full HouseAnon
- i used to think poo was a worm in me that ate leftovers that my tummy didnt want, that was full and left.— vanessa
- I used to believe that the oddly-shaped clouds were made from oddly-shaped sheep— Dickson
- I used to believe that all dessert was birthday cake.— David
- i thought hot dogs were made from real dogs and sum tasted good sum didnt.— Wayne