At any rate, I had my question answered. Stamina foods don't affect regen rate at all, so averaged over time they don't affect how often you can act, how nimble you are, or any of that. Whether you can manipulate a higher max stamina in combat to usefully exploit bursts of action followed by lulls of no action to get more backstab bonuses does not change the fact that no, you're not getting more actions overall, you're just clumping them together in bursts followed by longer lulls, so no, stamina foods won't help you chop wood faster, or mine faster, or run faster, or hit more often, or any of that other false advice people keep saying.

Again, this is all dependant on regen rate not being affected by max cap. If it *is* affected by max cap, as in "get 10% of max back per second" or something like that, then it would be different.