Get a vacuum jar, not a heating pack

A vacuum-insulated food jar is the best way to keep a warm meal hot for hours — heating packs and electric warmers are either fiddly or need an outlet.

Thermos and Zojirushi make the ones worth your money. They’re basically thermoses with wide mouths and a little foldable spoon. Fill them with something stew-like — chili, pasta, curry, rice bowls — and it’ll still be hot at noon if you heat it up right before leaving. Zojirushi tends to hold heat longer, but both are great.

Heating packs, like the disposable hand-warmer type, are a trap. They add a little warmth for a while, but they can’t hold a stew at safe temperature, and your food ends up lukewarm by lunch. Those insulated bento bags with heat packs in the lid? Same problem. They’re for keeping your food from getting cold, not keeping it hot.

If you want to bring separate dishes — like a proper bento with meat, rice, and veggies — the move is an electric heated lunch box, like the HotLogic Mini. It plugs into the wall at your desk and reheats or keeps food at a good temp. No batteries, no packs, just a warning: you need an outlet and you need to remember it’s plugged in.

So it comes down to this: one-dish comfort food, get a vacuum jar. Multi-dish variety, get an electric warmer. Skip the heat packs entirely.

Your lunch will thank you.