Monkeys eat baby leaves

Meanwhile, I just read in National Geographic about a monkey breed that mostly eats young leaves. I may return to eating some spinach - though it's really expensive, not the least because somehow they have to get the leaves off the stalk. This all makes me think we're not really supposed to eat the stalk, at least not the part by the root. Maybe the plant doesn't mind that we eat the small leaves as long as we poop after eating to nourish the plant.