Size the lunch box to the appetite, not the body

You pick a lunch box based on how much food actually goes in it, not on whether the person is “small” or “large.”

For a small adult who packs a normal lunch — sandwich, fruit, maybe a snack — a compact box in the 1.5 to 2 liter range is plenty. It fits a civilized meal without taking up half the work fridge.

A large teenager is a different animal. They’re often growing, occasionally hungry enough to eat the fridge, and they tend to pack double sandwiches, chips, leftovers, and two snacks. For them, go bigger: 2.5 to 3.5 liters, or a bento-style box with several compartments. That extra capacity disappears fast.

Just don’t overthink it. If you can lay out the actual food they’ll take and it fits with a little room to spare, that’s the right size. Body size is a rough guess at best — some small adults eat like horses and some tall teens eat like birds.

A hungry teenager with a tiny lunch box is a sad sight. Get the big one.