Personally, I think that a food system, on a character level, would be fairly out of the scope of the game's design goals. Your glyph sustains you, right? At least, when it's not shouting "Hey, listen!", heheheh.
As a part of the macro game, though, it would likely be extremely interesting. I would say that the general gain from dealing with the food system should be that your survivors are much healthier, ergo when you die, you have a better pick of survivors.
If you ignore the food system, when you die, your survivors are going to be, on average, of lesser quality (likely affected by game difficulty, tier, continent, etc, to some degree). Maybe even have the survivor crop start at a low level of health, and make supply raids, farming ventures, hunting trips, fishing trips, and the like mission-styled events that would give you the ability to raise that level, therefore raising the general health of your survivors (for a timed period, which, if ignored, goes down slowly).
Assuming that your survivors started at a low level of health, there would only be carrot and no stick in regards to dealing with the macro game food system.