Maybe there are thermos containers out there that really keep food hot. But we haven’t found them yet. I always pre-heat the thermos with boiling water and pour in the very hot soup, but my son reports that by lunch the food is only just warm. I have two college aged kiddos that bring lunch to campus every day. No microwave or fridge is available for commuter students. So earlier in the semester I made a thermos cozy. They reported it helped a lot.