And, sometimes when they do discover it, they are more than surprised. They did not know that cheese comes from milk and milk comes from cows. Cheese actually has mold growing on it in order to arrive at a certain flavor.
They did not know that good bread has a real crusty crust and does not come out of the oven sliced.
They did not know that meat comes from an animal and you have to cook it not just order it.
They did not know that chicken noodle soup starts from chicken stock which requires boiling chicken.
And, they did not know that they could grow their own veggies, just by getting their hands dirty.