Food is obtained from producing livestock units, such as Tech's cow or the Egypt's chicken. The amount of food provided per unit varies with the unit (for example, the cow provides 10 food and the chicken provides 5).
Most non-building units require food, and without food, will slowly loose health. Units generally require 1-3 food each. Being a consumable resource, it's necessary to keep stocks in the resource high. Each turn a certain amount of the resource will be used. The balance for the turn (production minus usage) is indicated inside brackets along the stock. If it is negative, the stock decreases. If the stock gets negative, units will take damage. When there is not enough food, no new unit can be created, but existing units can still be saved by quickly restoring the food supply.