Just to tangent a bit, that's similar to how my dad was raised - you cleared your plate.
And in later life, he attributed his serious problem with his weight entirely to that. So he never gave that rule to us, he wanted us to only eat what we wanted to eat (within reason). Unfortunately, he still didn't want to waste food, so if he thought we left enough to eat, but not enough for leftovers, he'd eat it....
His rule was "I am not a short-order cook". We could eat what was made for dinner, or we could make something ourselves (assuming we could make something ourselves, of course - in pre-cooking days, that didn't happen) or we could not eat.
Re: Regarding the school-lunch programs:
And in later life, he attributed his serious problem with his weight entirely to that. So he never gave that rule to us, he wanted us to only eat what we wanted to eat (within reason). Unfortunately, he still didn't want to waste food, so if he thought we left enough to eat, but not enough for leftovers, he'd eat it....
His rule was "I am not a short-order cook". We could eat what was made for dinner, or we could make something ourselves (assuming we could make something ourselves, of course - in pre-cooking days, that didn't happen) or we could not eat.