Keeping food warm for 4-5 hours without a microwave can be challenging, but there are several methods you can try:
Insulated containers: Invest in a good quality insulated food container. These containers are designed to keep food hot for several hours. Preheat the container with hot water for a few minutes before adding the hot food. This will help maintain the food's temperature for a longer time.
Thermos flask: A thermos flask can also keep food warm for hours. Preheat the thermos by filling it with boiling water and letting it sit for a few minutes. Then, replace the water with the hot food you want to keep warm.
Double-walled containers: Similar to insulated containers, double-walled containers can also help retain the food's heat for a more extended period.
Hot water bath: If you don't have any insulated containers, you can use a hot water bath to keep the food warm. Fill a large container with hot water and place your food container inside it. Make sure the water level is high enough to cover the sides of the food container but not so high that it spills into the food.
Use towels or blankets: Wrap your food container with towels or blankets to provide additional insulation and retain the heat.
Preheat your lunchbox: Before adding the hot food, preheat your lunchbox by pouring hot water into it, closing the lid, and letting it sit for a few minutes. Pour out the water and add your hot food.
Keep the food in the oven: If you have access to an oven, you can set it to the lowest temperature and keep your food inside until you're ready to eat. However, make sure the oven is turned off before placing the food inside, as the residual heat will be sufficient to keep the food warm.
Remember that it's essential to keep hot food at a safe temperature to prevent bacterial growth. If you're not sure about the food's safety after several hours, it's better to consume it immediately or refrigerate it and reheat it later when a microwave becomes available.