A typical conversation with my four year old:
the boy: Daddy, can I have a snack?
me: But we just ate dinner. And then you had Jello!
the boy: But that was dessert. I didn't get a snack tonight!
At first I was confused, but I did a little research and learned that growing boys have an anatomy that's a little different than the rest of us.
And they're not full unless all of their stomachs are full.