I'm fairly new to the game, but it would seem to me that it makes the game more interesting (and realistic) if food is a "zero sum game". The scarcity of resources means that no realm can afford to be complacent, it gives them a motivation to go to war and engage in diplomacy. It's the same in real life. Scarce natural resources, e.g. oil, water, diamonds, etc. are among the root causes of many conflicts. If the developers' intent is for every realm to be fed, then why have it as a variable?
We've been studying the way food works in the game for some time now, and we can say with confidence that this simply does not work.
Because of how quickly regions deteriorate without food, there is really no way for a realm that lacks food to go out and get it.
