Ask HN: Why do we kill and eat other living beings?
Because human physiology evolved in an environment in which critical nutrients were sourced predominantly (^exclusively 
animal in list below) in the flesh of animals.<p>Examples of key animal-based nutrients:
Vitamins: A, B6, B12^, D3^, F, K2^; 
Amino Acids: Creatine, Carnitine, Carnosine, Taurine;
Heme Iron; CoQ10; CLA; Cholesterol<p>This list does not include nutrients&#x2F;vitamins which often lead to deficiencies when sourced in plants, due to very low bioavailability or antinutrients which block the absorption of the nutrients.<p>So, why do we kill and eat other living beings? Because we evolved this way and it is part of our natural diet.