Four ways of getting food
I categorize food sources by the activity required to get the food. These are:
- Gathering
- Hunting
- Farming
- Breeding (animal husbandry)
Gathering
Gathering means collecting food, generally from plants or other static sources, that is already present in the world. Examples are apples growing on trees, mushrooms or berry bushes. The advantage of gathering is that it has no prerequisites; you do not need to craft any tools, place any nodes, or going through any motion other than walking up to the food and taking it. This makes it an excellent food source for starting on a new world.
To balance this (in a ludic sense, remember!), gathering needs to be less useful past the starting phase. The simplest solution would be to place these food sources at map generation time and never again afterwards. Gathering is then only useful while exploring, and not for settlements. Alternatively, the food could regrow in the place it was originally generated, without the possibility of transfering it. For example, apples would (re)-grow on apple trees, but players cannot place apple trees, or at least very unreliably. Or mushrooms could generate randomly without players being able to influence when and where they grow.
Hunting
Hunting means looking for suitable mobs, killing them, and taking their meat. It is similar to gathering, in that the food source is already present in the world, or reenters this, without player intervention. Examples would be deer, boars, rabbits, or caramel golems. The difference to gathering is that it requires more skill and preparation to pull off. Weapons help with hunting, especially ranged weapons, and prey will generally try to escape or fight back.
The payoff needs to be that a successful hunt yields more food, or more satisfying food, than gathering. The balancing requirement is that hunting, like gathering, is not planable or influencable. Prey cannot be bred, or even tamed. They may despawn if map chunks are unloaded, or if too old. If they do spawn after world generation, it is generally unpredictable.
Farming
The difference between farming and gathering is that farming requires an investment. You need to craft tools, prepare land, build lattices and irrigation, and actually plant the stuff. Farming also offers the nice game mechanic of choice: players need to decide how much of the crops to eat, and how much to plant.
This mechanic is broken, for example, in the wheat in MineCraft, if you're familiar with it. If not, here's how it works there: players cut grass to gather seeds, which grow into wheat stalks when planted. When harvested, the stalks drop seeds and ears of wheat. It's the ears that are edible (after processing), while the seeds are not. So the seeds get planted and the ears get eaten; no choice necessary. If I ever write a farming mod, wheat will only drop seeds, which can be planted or eaten.
Farming also has exponential growth: a single carrot field yields enough to plant two carrot fields, which yield enough to plant four carrot fields, which yield enough to plant eight carrot fields, and so on. From a ludic perspective, it therefore makes sense to have farmable foods be not very satisfying, to require a medium to large farm to keep up with your hunger. On the other hand, care must be taken that working on the farm takes up as little time as possible. Players should not have to spend half their playtime harvesting and replanting unless they really want to. Again, this is seen from a purely ludic viewpoint.
Farming can and should tie in with gathering: players must start out gathering, because they will starve before they can build up a farm that is big enough (and then respawning will reset their health and hunger, but we'll ignore that ;-) . Ideally, the farm starts paying off around the time that gathering is no longer feasible for a given area. For normal player activity, that is: don't calculate it so tight that players don't have time for doing anything else but farm at the start :-P
Breeding
Breeding is to hunting what farming is to gathering: a long-term investment with substantial requirements. Animals need to be found, tamed, collected, protected, corralled and fed. For ludic purposes, this should be different enough from farming. If a player goes out each morning and harvests all their wheat, then replants half of it, then breeds all their pigs, then slaughters half of them, nothing is gained.
Some potential differences: it may take more time for breeding to match farming in food output. Breeding may take less area than farming for the same yield. Building fences and gates is probably more infrastructure work in the beginning, but houses more animals. Animals may require feeding; this will be different food than what they produce, meaning that unlike farming, it is not self-sustaining. Animals may need protecting from hostile mobs. Like in hunting, animals may run away, or even fight back, during harvesting. Animals may die of old age, though this is only a difference if crops don't wither if ignored.
Conclusion
The points above try to provide some game mechanics for food sources. If you are putting together a subgame, or a server, or just writing a single food mod, please think about the ludic consequences, the game mechanics, that you create. Having 50 different farmable plants is impressive and realistic and fun, but if they all "play the same", I feel that potential is being wasted.
A last example or thought experiment: fishing. What can fishing bring to the table in terms of game mechanics? If fishing requires a fishing pole, it's already different from gathering, because of the tool requirement. If there's no exponential growth (can't use two fishing poles at the same time), it's not comparable to farming either. There may be no skill or uncertainty involved, but it may need constant player presence and patience, unlike farming, hunting or breeding. To branch fishing out into other fields: what about nets that are placeable in water and can be emptied each morning? There's no positive feedback loop, but a large infrastructure requirement. Nets may or may not require upkeep, whatever is different from other food sources. Or fish might be bred in pools, in which case, how is it different from breeding pigs? Do fish breed without interaction? Without needing to find wild fish to get started?
Whew! Those are my thoughts on the mechanics of food sources. Feedback welcome, and thanks for reading!