Skip the boxy lunchbox

Skip the boxy lunchbox—the slimmest options are soft-sided, sleeve-style insulated bags that slide into a backpack flat against the back panel, like a binder or a small laptop.

Hard-sided lunchboxes are the problem. They keep their shape whether they’re full or empty, so you’re paying for dead space and a bulge you can’t compress. A flexible, flat insulated bag (roughly the size of a book or a 10-inch tablet) wastes nothing and squeezes into the gaps between your laptop and your notebook.

The shape of the container inside matters just as much as the bag. Wide and shallow beats tall and narrow: a bento-style box or a shallow 2-cup container holds a real meal—sandwich plus snack, or a grain bowl with veggies—in about two inches of height. Stack a second flat container on top if you need more food, not a deeper one.

One trick: stand the lunch bag upright, like a file, against the back of the pack. It uses the depth of your backpack instead of eating the whole floor, and it stays accessible without unpacking everything on top of it.

Your backpack will finally close without you sitting on it.