Bento Boxes do keep food warm for at least a few hours.
If you place the Bento Box with warm food in an insulated bag then the food will stay warm for around 4 hours.
A bento is a single-portion take-out or home-packed meal of Japanese origin.
Outside Japan, it is common in other East Asian culinary styles, including Chinese and Korean cuisines, as rice is a staple food in East Asian cuisine
The great thing about bento boxes is that you can build any kind of meal you need thanks to the compartments.
The best option is to use it to fulfill your daily food groups, even packing it the night before, because compartments will prevent things from getting soggy.
The word bento is originated from the Japanese language which means lunch box.
During the fifth century, Japanese man used to carry compact meals so called Bento when going fishing and hunting.
Through that period Bento boxes contained white rice, millets and potatoes.
Bento boxes have grown in popularity, not just because of the nutritional value of the meals, but also because they're also aesthetically pleasing.
Often foods are arranged in the bento to look like popular characters like Snoopy, the minions and, as in this case, the Simpsons.