Eating stamina foods isn't going to improve your long-term work rate, since you'll be spending and regaining at the same rate either way. Chopping wood, mining ore, or working farms will take the same amount of time, you'll just be able to do larger bits of your work between quick rests.

What it's for is improving your burst performance - being able to do more immediately before getting tired out. This makes it useful for fishing, combat, or reactions during exploration - each areas where you're dealing more with individual actions and the success of each is highly dependent on how much stamina you can put into it.

The most important thing is making sure you maintain your Rested buff, which doubles your stamina regen rate while active (and having both Resting and Rested going at the same time makes it 3.5x as fast as without), as well as doing your best to avoid debuffs that slow your stamina regen (Cold and/or Wet, for example).