Yeah, this by far is the most annoying problem I've seen. I've had instances where I had 400 food, put the game on 1/2 speed and gone to bed. I wake up the next morning and there's no food, 40 minutes to harvest and everything else is barren. I have 18 people in my village.
I'm resorting to playing it manually at normally speed, and checking the pot to make sure there's food every few minutes and looking for mushrooms. I've got everybody cranking on research just so I can get to 90K tech to buy Farming 3. It takes me about 1 hour to get about 15-20K tech. But I have to sit in front of the game the whole time. This is my first village, and had I known, I would've kept my population down to 12-14 to make sure I don't run out of food. Unfortunately, I had one founding woman who had some parenting skills and periodically she'd hook up with another guy and out comes another mouth to feed, even if I had her farming instead.

I dunno, I can see this kept this way by design, but it would've helped if I knew how much the farm could support optimally.