No matter how well-intentioned it is, it's an anthropological fact that if early proto-human cavemen didn't start eating meat, they would never have gotten the bursts of proteins & fats necessary for our brains to grow more and more complex and achieve sentience. The human brain is made of very fatty tissues you don't get from plants alone.
As further proof that humans evolved to an omnivorous diet of meat and plants, we evolved sharp incisor teeth designed to tear through meat, our tongues evolved "salty" tastebuds to get off on the flavor of meat (just as we evolved "sweet" tastebuds to enjoy fruit as well), and we have some of the most corrosive stomach acid on the planet - perfect for dissolving meat. If humans were only designed to eat plants, our stomach acid would be pure biological overkill. Our digestive tracts have evolved both qualities of herbivores and carnivores, which suggests we thrive best on an equal mixture of plants and meat in our diets.
As further proof that humans evolved to an omnivorous diet of meat and plants, we evolved sharp incisor teeth designed to tear through meat, our tongues evolved "salty" tastebuds to get off on the flavor of meat (just as we evolved "sweet" tastebuds to enjoy fruit as well), and we have some of the most corrosive stomach acid on the planet - perfect for dissolving meat. If humans were only designed to eat plants, our stomach acid would be pure biological overkill. Our digestive tracts have evolved both qualities of herbivores and carnivores, which suggests we thrive best on an equal mixture of plants and meat in our diets.