Food resource differs from other resources in a way that isn't entirely obvious (there may be other resources acting in a similar way as food).

What I mean is that the food doesn't grow / accumulate, while other resources do. When you build a building that requires food you could (and I did) get confused what will that cost and when food reached 0 I was trying to figure out how to not make my population starve until I figured out it is a state resource. (BTW I think not accumulating food is a great idea. I wasn't easy to store years worth of food anytime).

Tomas