Yes, it's a big problem, but when I read the first column of Hubei Shi Jing Life Association, they recommended a lunch box (Baoyi Slow-heating Nutrition Lunch Box), so I bought it and tried it. Now I bring it to work every day, saying that it will not destroy the nutrition of food. It is really good after use and the temperature is right. Even if it takes a long time to heat in advance, there will be no problem of long time. After all, it is the most important thing to ensure that the nutrition of food is not lost.