Get a wide, flat lunch bag, not a tall one.

The best lunch box for a tote is a wide, flat insulated bag — think bento style, not the tall brown paper bag shape.

Tall cylindrical or boxy lunch bags tip over the second you set your tote down. A wide, flat bag sits on the bottom like a stable base and barely moves. The extra footprint also spreads the weight out so it doesn’t pull the tote sideways. The PackIt Mod or a generic rectangular bento bag works well — anything with a base wider than it is tall.

Inside, don’t trust anyone’s “leakproof” label. Use small reusable containers with snap lids for anything wet (dressing, yogurt, fruit). That keeps spills contained even if the whole bag takes a tumble. Throw the lunch bag in last, flat at the bottom, and your books or laptop go on top of it, not next to it.

Your sandwich will survive. So will your laptop.