I've also gathered some conclusive evidence: I don't eat meats, and I haven't died (not even once!).
But seriously, the fact that 10,000 years ago human-type creatures ate a lot of meat should be like number 76 on your list of arguments in the sustainability of diets debate.
Sorry, I'm greedy when it comes to my own wellbeing. Do I really care how sustainable my diet is if I have to suffer for 20-30 years with ailments the can be chalked up due to the deficiency of the diet itself?
But seriously, the fact that 10,000 years ago human-type creatures ate a lot of meat should be like number 76 on your list of arguments in the sustainability of diets debate.