The weather is getting cold, and the food in the company canteen is unpalatable and expensive.

Bring your own food and use an insulated lunch box. That's what I did at school. The food is still warm until noon, and the supermarket will go and see it by itself.

If you want to eat hot food, soak the lunch box in hot water, because of heat transfer, the heat released = the heat absorbed by the lunch box.

(Not the rice soaked in it, but the lunch box)