Upkeep is the amount of food your army consumes every hour. If your upkeep exceeds your production you will run out of food and will not be able to produce any troops and you will not be able to upgrade any buildings. Most of your research upgrades also require some amount of food. Upkeep can be helped by conquering lakes and grasslands thereby boosting your food production. Wall units do not affect upkeep but are relatively weaker because they are not enhanced by vigor , honed blades , hero boosts unless you keep a hero assigned to construction.
Troops will not defect:Edit
It is very important to note that, unlike most games, your troops will not defect if you run out of food. This leads to several great upkeep managment strategies.