This is an Australian professor giving a lecture about his advocacy of eating a high meat/high animal fat diet.
It's not that all or most of what he says is untrue; it's that he is leaving out other considerations that are important. And first I'll say that any dietary arguments that are based on Evolution are inherently flimsy since the Theory of Evolution is so flimsy. And I am not saying that as a Creationist because I am not one. But, the idea that life on Earth developed and changed and acquired increasing complexity based on random mutations- pure genetic accidents- that were acted on by "natural selection" is not just dubious; it is mathematically absurd. So, I don't really like to hear anyone use Evolution as the basis for making dietary claims- and there is far too much of that.
But, here is an example of an important point that went unmentioned. How can humans require a high-protein diet/low carbohydrate diet when human breast milk is extremely low in protein and extremely high in carbohydrate? To be blunt: human milk is the lowest protein milk among mammalian milks, and by a wide margin. And, human milk is also the highest carbohydrate milk; it is by far the sweetest milk of any.
And even though human breast milk has only 1% protein by volume (sometimes measured as low as .9%, and I hope you caught that decimal point) human babies can easily double their birth weight in 9 months on a diet of breast milk, and some do it in as little as 6 months. So, even though humans are slow to grow and mature compared to most other mammals, the fact is that the first year of human life is a period of very rapid growth, and it all happens on a very low-protein diet.
And keep in mind that a human mother makes low-protein milk no matter how much protein she eats. She can't force her breasts to churn out a higher protein milk by consuming more protein.
So, if rapidly growing babies can grow and develop and be sustained entirely by low-protein breast milk, why assume that a human adult who is not growing at all requires a high-protein diet?
Keep in mind that I am NOT opposed to eating dietary fat. I do not demonize dietary fat like Dr. John McDougall and others do. I think it is perfectly natural and normal to eat fat. But, I think the best fats are plant fats, such as avocadoes, raw nuts, and oil-seeds. And I am not opposed to using high-quality, extra-virgin olive oil. I think all of these are good, and I partake of all them, and I stay slim while doing so. But, I have to think that all the evidence shows that it is best to limit meat consumption to small amounts- that is, if you don't eliminate it completely. The idea that we should feel compelled to eat meat, and large amounts of it, and just because our ancestors did is ridiculous.
Surely, if they were living in Northern Europe during an Ice Age, they had to eat meat, and in large amounts, because for most of the year there was no plant food available to them, and the storage of plant foods wasn't yet practical on a large and efficient scale. But, that is not the case today. Today, even if you live in St. Petersburg, Russia, the most northern major city in the world, there is plant food available in abundance the year round. The Caveman did not have what we have. And having what we have, there is no good reason for us to eat the way he did.
Look: the first thing you want to do is eat an abundance of fresh fruits and vegetables, and I presume that like most people you have access to them in wide variety all year. Then, there are other plant foods with proven health-protective effects, such as nuts and also beans and legumes, which are excellent foods. There are also whole grains, which are popular to trash these days, but I like them, and I eat them. Now, in addition to that, if you want to keep some room in your diet for meat and animals foods, I don't say you can't or shouldn't, but how much room is there? If you obtain for yourself a full ration of all the disease-preventing, health-protecting plant foods available to you, unless you are an extremely big eater, you are probably not going to have much room left for animal foods anyway.
So, as I see it, the important thing is not to decide to be a vegetarian but to decide to eat plant-strong. Good sense should tell you that plant-based diets are the way to go in the 21st century. I don't say that it has to be exclusively plant, but at least make it mostly plant. And don't let bogus arguments based on Evolution talk you out of it.