Maybe make an army food supply, similar to war chest. If the region is starving, food comes from war rations. This could also be an excellent way to reintroduce the steal food looting option- put it in war rations.
If you played with the potential feature some, it could really make being an army sponsor lucrative if you could sell/buy war rations in market places.
Imagine looting the food of your enemy, and then selling the surplus that would rot to your starving ally.
I don't know how complicated that would be to implement, but I really like this idea.
