eat up his weight in groceries
Someone who eats so much, they might as well be a human fridge. If they don’t work out, they’ll be a giant who could bench-press a cow.
He eats like a man who just escaped a candy factory.
That girl ate a whole cake, a pizza, and a bag of popcorn like it was a food coma party.
He eats so much, his pants could be a shopping bag.