Food is made for giving energy to your characters. Firstly you need to cook it and then you'll be able to eat it. You need to use the food you cooked, in order to move on with the food making. To use cooked food, you need to click on the table, then transfer the food from the cells to the table. After that, the plate with cutlery will appear. Click on it and the characters will begin to eat, and the food will disappear.