Food is a renewable resource required for starting battle missions.
 
Food can be produced by the Farm. The higher the level of the building, the faster it makes good and the more food it can store before collecting.

Food is spent each time you start a Campaign or Tower of Trials mission as well as when you search for an opponent in Arena. As you progress in these modes, more food will be required for each mission. If you lose a battle or flee, the food you spent is not returned to you.

Workers in the Town Hall do not affect the food production rate.