We're told we need to eat animals and their secretions to obtain certain nutrients, such as calcium, iron, B12, Omega 3 fatty acids, but what we're not told is why the animals' flesh and secretions contain these nutrients in the first place. Here are a few clues. Calcium = mineral found in the ground. (Cows [are supposed to] eat grass, which contains calcium.) Iron = mineral found in the ground. B12 = grows on bacteria. (Bacteria is attracted to, well, corpses.) Omega 3 fatty acid = a type of polyunsaturated fat found in plant foods. (Fish eat algae, which contains Omega 3s.) See where I'm going with this?