If I feed my kids 3 meals a day, they just don't eat all of what I make them (they are 5 and almost 2). I loathe wasting food, and they probably leave about a whole meals worth altogether if I feed them 3 times a day. I usually give them a little something for breakfast, like half an apple - or if they're not hungry when they wake up they'll have something mid-morning - then the odd little snack through the day and then a full meal at dinner time. They're hungry enough by then that they'll eat it all. They never complain of being hungry and rarely ask for food.
Similarly I never have breakfast in just never hungry in a morning, I always wait til lunchtime.
AIBU to think that, for some, 3 meals a day is excessive?
I imagine it will aaaaall change come teenage years