Earlier I saw a post which had a picture of a dog and a pig and asked, "Why would you eat one and not the other", to which I replied, pigs taste good but dogs are too gamey. Really any lean meat not so flavorful. Obviously it was trying to make those of us who are carnivorous or at least omnivorous to feel guilty for eating pigs.

But then I got to thinking more, what allowed humans to evolve such large brains? And the answer to that is the combination of being omnivorous / carnivorous because meat is much easier to digest and extract energy from the plants, that is why cats have a very short digestive tract and cows need three stomachs and a very large digestive tract. And then cooking, cooking meat allowed us to digest it and extract energy from it even easier. And our brains consume more than 1/3rd of the calories we eat. Brains are very energy hungry organs.

And if we ate only vegetables, our brains would be starving for energy and not function well. And for proof of that all you need to do is spend about 30 seconds talking to any vegetarian.