I think the best quick solution/implementation would be to have an ini option(s) for "base eaten/drunk stack size". Set the default as "1", like it is now, but let the player mod their game to need more food/drink per visit. This has several advantages over changing things permanently in the game. It doesn't screw over people with low FPS computers, since it's optional they don't have to farm more with their meagre dwarves and can still build stuff. Plus, eating more, but not eating more often, wouldn't lead to double the breaks (which would really cripple dwarf productivity).
But I really think the key issue isn't lack of consumption: in the early game, labor is really restrictive and consuming more would hurt growth. It's that in the end game you end up with tons of excess labor and nothing to use it for. Farm plots balance is best fixed by causing more plot size needed to feed 1 dwarf (possibly making this an ini parameter). Right now, it's basically not a constraint at all. Games are fun because of hard decisions. When 1 10x10 room full of plants can feed the whole fort, there's no challenge to that. How can that be fixed? Here are a few possible options for farming fixes, that should be really simple to program. Needing bigger farms as the population grew would be a nice realism, rather than the "build once" the it's good forever model we have now. Farms could be forced to be bigger by some combination of these. The first two can already be implemented in raw mods:
1- plants take a lot longer to grow (possible early fort starvation here, means you need more plots)
2- more growing season restrictions (need to plan better for which crops).
3- plants don't produce big stacks(need more labor per plot + bigger plots)
4- farm plot tiles take some time to recover after harvest before being replanted (need more plots, but no extra labor or early starvation). i like this option. To very simply track it (on a programming level), the game could place a "virtual plant" ("recovering" or something) that takes some set grow time after the last crop is harvested. This would be a quick and dirty way to model leaving farms fallow to recover from planting.
One thing I would prefer in the end game, is to export the wealth more. Some ways to make that fun would be to have your king request resources to help with the war effort vs the elves/humans/goblins. Keep track of the fortress' war contributions (which could be resources and equipment to start with, but eventually expand to providing trained soldiers, which would give a LOT of contribution value), which would accumulate for "favors" bestowed on your fortress. This could be made a condition of gaining higher noble titles. Output gets used up, frees up FPS and also makes you feel more integrated into your dwarven civilization. Later on, this could include sending out forces to build colonies and border forts. Colonies could require years of resource donations to grow them faster, and could be situated in locations which can produce resources your home colony is lacking. Forts would require a sizable chunk of trained soldiers to man them and need regular food and drink shipments (also dwarves out of the fortress = less FPS drain).