Make the lunch box too big to slide

The trick is to buy a lunch box that matches your bag’s inside dimensions, not one that fits your appetite.

The sliding happens for a simple reason: the lunch box is smaller than the space it’s sitting in, and most are rounded or slick, so they roll and shift with every step. The fix is to make it physically unable to move. That means rectangular, soft-sided, and close to the same footprint as the bottom of your bag’s main compartment. Bring a tape measure to the store. Nobody regrets that.

Two things worth hunting for. One: a lunch bag that’s tall and narrow, not wide and shallow, so it stands upright against the back of a backpack like a book. That shape also survives a messenger bag without tipping over. Two: a luggage pass-through strap or vertical handle on the back. Slip that over your backpack’s top handle or an internal compression strap, and the lunch bag is now strapped to the bag itself instead of rattling around free.

If you already own a lunch box you love, cheat: drop it in a mesh pocket, wedge it between bulkier items, or buy a vertical insulated bottle bag and stick it straight into a bottle pocket. Those stand up on their own and never go anywhere.

Future sandwiches deserve better than ending up shredded at the bottom of your bag.