From what I gather

there is NO generally accepted scientific theory that holds that eating large amounts of animal protein caused us to increase our abilities regarding abstract thought. Far from it! We don't even know for certain the amounts of meat our ancestors ate. It's just guesswork.  Though a common and well accepted guess We are primates. Primates eat plants. Our ancestors most likely ate just like other primates. Mostly plants! We are apes. Gorillas eat 98% of their calories from plants. Chimps eat 96% of their calories fro.

himps and bonobos are our closest relatives. They get over 96% of their calories from plants. About 2% from insects and 2% from meat. We would be SO much healthier if we kept our meat consumption as low as that.

the common misconception people make is that they think eating meat was a fad that started when Homo sapiens diverged from Pan troglodytes nearly 7 million years ago. It isn't. It's always been in our nature, yet we made much, much greater use of it in order to expand our range from the tropics all the way to the Arctic. Ability to survive on something does not equal that thing being IDEAL for health or longevity! We are primate. (There is no question of that.) Of more than 250 species of primate, all but one eat the vast majority from plants. We are most closely related to the great apes. ALL eat the overwhelming majority of their calories from plants. No less a scientific genius than Carl Linnaeus (the guy that created our system of animal classification) looked at the comparative anatomy between humans and other animals and declared we should be frugivores (fruit-eaters).

Man relied on meat more and more as we expanded our range into colder regions. But, that didn't change the facts that plant foods are more ideal for our health and longevity.
Michael J. Benton, British paleontologist, Fellow of the Royal Society of Edinburgh, and Professor of Vertebrate Paleontology in the Department of Earth Sciences at The University of Bristol wrote: "The apes, Hominidae, today include the gibbons and orang-utan ... the gorilla and chimpanzee ... and humans."
Carl Linnaeus writes: “Man’s structure, internal and external compared with that of the other animals, shows that fruit and succulent vegetables are his natural food.” 
Jared Diamond is a professor of anthropology at UCLA. Diamond has written off the notion of man the hunter as a romantic myth: “Big-game hunting added little to our food intake until after we had evolved fully modern anatomy and behavior.” Instead, our earliest ancestors lived on the wild fruit, nuts, seeds and tubers that they gathered. Mr. Diamond puts it succinctly: “I doubt the usual view that hunting was the driving force behind our uniquely human brain and societies. For most of our history, we were not mighty hunters but rather sophisticated baboons. And what food makes up the bulk of a baboon diet? Fruit, of course. So, for most of their history, humans were fruitarians."

Human breast milk is about 1% protein, and almost 8% carbohydrate (mostly lactose). That low level of protein is the perfect food for a newborn that is increasing its body weight faster than at any other time in it's life. Why would a fully grown adult need the same amount of protein as a baby who is doubling its weight every few months? We don't. We need less. The average American meat-eater, who's eating meat and dairy products with every meal, might be getting 35-50 percent of his calories from protein! Maybe more. (Plus, a ton of saturated fat.) It's absurd. This is why we are obese. This is why we are dying of heart disease. Again, human breast milk is LESS than 2 percent protein---for the fastest growth spurt of our entire lives. Human adults should eat fruit and veg. That is our natural food. Fruit and veg is what primates eat. (If you want to add very small amounts of animal protein from termites and mice, it's probably okay. Personally, I don't think we need that.)

thoughts?