Simple answer is, vegans and vegetarians would be dead if we were ‘meant’ to eat meat. Now, unless we are all well educated zombies, the fallacy that is needing meat to survive will forever remain a fallacy.
Humans have always eaten meat… right? No, actually we haven’t. The best evidence for what we’re optimized to eat is our digestive system.
A carnivore can eat rotting, bacteria-ridden flesh completely raw without getting sick. They have stomach acids that kill the bad stuff and allow them to digest the rest without puking their guts up. Their stomach secretes powerful digestive enzymes with about 10 times the amount of hydrochloric acid than that of a human or herbivore. The pH is less than or equal to 1 with food in the stomach, for a carnivore or omnivore. For herbivores and humans, the pH ranges from 4 to 5 with food in the stomach. Hence, man must cook his meats. Ever try to eat road kill? Or a freshly dead chicken, completely raw? Give it a shot and let me know how it works out for you. E. Coli bacteria, salmonella, campylobacter, trichina worms, parasites, or other pathogens would not survive in the stomach of a lion.