Get the stainless steel lunch box.

Stainless steel and glass are the safest lunch box materials — and the gap between them and plastic isn’t close.

The BPA problem is real, but “BPA-free” isn’t the clean win it sounds like. Plastics marked with recycling code #7 often contain polycarbonate, which leaches BPA into food when heated or when it touches acidic stuff like tomato sauce. And when manufacturers reformulate to drop BPA, they usually swap in BPS or BPF, which your hormones treat about the same. Chasing “BPA-free” labels on plastic is whack-a-mole.

Metal and glass don’t have this problem at all. Stainless steel is the best everyday pick: light, durable, and completely inert. Glass is equally safe but heavy and breakable. Food-grade silicone is a solid third option if you need something flexible — just make sure it’s actually food-grade, not a cheap knockoff.

If you need plastic, polypropylene (#5) is the least-bad choice and most bento-style containers use it. Just don’t microwave it, don’t run it through the dishwasher, and toss it the second it gets scratched or cloudy — scratches are where leaching starts. Also avoid melamine, which is common in kids’ “bamboo” or molded plates and can leach into food, especially with heat.

Your lunch shouldn’t come with a side of endocrine disruptors.