It takes 40 black olives to make 1 tbs. of olive oil. We would never eat 40 olives, but we take the oils from them to create one serving size (120 calories) of oil. On top of it, we usually eat more than 1 tbs. of olive oil. We should use cooking oils very sparingly (even if they're called "healthy oils") and try to eat foods in their whole form, in context of their other parts... the way they were meant to be eaten.