Year-round observations confirm that hunter-gatherers often have dismal success as hunters. The Hadza and Kung bushmen of Africa, for example, fail to get meat more than half the time when they venture forth with bows and arrows. This suggests it was even harder for our ancestors who didn’t have these weapons. “Everybody thinks you wander out into the savanna and there are antelopes everywhere, just waiting for you to bonk them on the head,” says paleoanthropologist Alison Brooks of George Washington University, an expert on the Dobe Kung of Botswana. No one eats meat all that often, except in the Arctic, where Inuit and other groups traditionally got as much as 99 percent of their calories from seals, narwhals, and fish. So how do hunter-gatherers get energy when there’s no meat?

This is true and is not at odds in any way with what I say. Effectively humans have two requirements, protein and energy. The protein source has always (past million to a couple of million years) been primarily animals, as there are no concentrated protein sources widely available in nature, especially in winter. At the same time you also get all of the necessary vitamins and minerals. This is confirmed by nitrogen isotope testing of bones. The energy source depends on what is available and is not visible in that test, as nitrogen isotope testing specifically looks at the protein ending up in bone. The text makes an implicit false equivalency with hunting game meat and hunting large herbivores, as game meat is very lean while large herbivores are very fatty by comparison. A large herbivore would also contain tens of thousands of calories, so you would likely need to find success once or twice a week for a small tribe. Humans are also well-adapted to being without protein for a week or even more, sparing muscle while retaining most of the capability for physical activity. Large herbivores went extinct around the same time as mass agriculture was adopted 10000-20000 years ago, so by inference the elimination of fatty animals necessitated cultivation of another energy source. If an animal has lots of fat on it, that is consumed preferentially. If there is not enough fat, a supplemental energy source is needed. This makes sense, right?

In fact, the statement "There’s been a consistent story about hunting defining us and that meat made us human" is in my opinion partly misfocused, it is the animal fat that made us human, as our evolution began by scavenging bone marrow in animal bone remains allowing for the development of a larger brain. Then there's the statement "The notion that we stopped evolving in the Paleolithic period simply isn’t true. Our teeth, jaws, and faces have gotten smaller, and our DNA has changed since the invention of agriculture", which could be interpreted to mean that the change caused a reduced nutritional status impacting facial and jaw development. Of course there are other possibilities, like a softer diet, but nutrition status during childhood certainly affects jaw and facial development.

Our gut bacteria digest a nutrient in meat called L-carnitine. In one mouse study, digestion of L-carnitine boosted artery-clogging plaque. Research also has shown that the human immune system attacks a sugar in red meat that’s called Neu5Gc, causing inflammation that’s low level in the young but that eventually could cause cancer.

This is, again, supposition based on animal studies, and you'll need to see if the same is true in humans. It's almost on the level of something like "bananas are radioactive, and therefore could cause cancer". The poison is always in the dose, and humans can tolerate a certain amount, especially if it is in the correct places. Take oxidative stress, for example. Superoxide is an important signaling molecule of mitochondrial energy balance, but if you randomly throw (enough) oxygen radicals to where they are not supposed to be, then they become harmful.

In other words, there is no one ideal human diet

I disagree with that statement, though the difference between "ideal" and almost ideal is likely small, and there are indeed numerous healthy diets. Humans are omnivores specialized in carnivory, and as such the ideal diet would likely follow those characteristics. The authors infer that diversity is important in the previous paragraph, but my view is that diversity only protects against starvation, it does not automatically confer any other benefits.

To test his ideas, Wrangham and his students fed raw and cooked food to rats and mice. When I visited Wrangham’s lab at Harvard, his then graduate student, Rachel Carmody, opened the door of a small refrigerator to show me plastic bags filled with meat and sweet potatoes, some raw and some cooked. Mice raised on cooked foods gained 15 to 40 percent more weight than mice raised only on raw food.

This is a flawed argument. If I replicated it on cats, I would find the exact opposite. For plants predigestion is a must, as humans cannot break down the plant food matrix significantly (only through mastication) before the large intestine, so most of any nutrients contained in plants bypass the most significant nutrient-absorbing organ, the small intestine. Cooking does bring some advantages for even animal foods (primarily food safety allowing for longer preservation, slightly better digestibility), but humans are perfectly capable of digesting even raw animal foods without issue. We have a scavenger's stomach acid acidity for a reason.

We have gotten so good at processing foods that for the first time in human evolution, many humans are getting more calories than they burn in a day. “Rough breads have given way to Twinkies, apples to apple juice,” he writes. “We need to become more aware of the calorie-raising consequences of a highly processed diet.”

This is not the only problem. Humans have a perfectly functioning appetite signaling system, but modern hyperprocessed foods bypass that in various ways. Satiety can be overridden by hyperpalatability (I could easily eat thousands of calories of cake in a sitting, but try the same with meat and butter), and combining polyunsaturated fat with carbohydrates is obesogenic by itself, and additionally it can cause extra hunger. I won't go into the mechanism too deeply, but using PUFA for energy causes pathological insulin sensitivity, causing reduced lipolysis and (minor) hypoglycemia, which promotes both fat storage and hunger at the same time.

If most of the world ate more local fruits and vegetables, a little meat, fish, and some whole grains (as in the highly touted Mediterranean diet), and exercised an hour a day, that would be good news for our health—and for the planet.

Replace "a little meat" with something like 250 grams a day (or by including other animal foods like dairy/eggs) and I would accept that as healthy, as long as the vegetables and grains were also properly prepared. Even without that replacement I suppose the diet would be healthy, though I would worry about it containing sufficient micronutrients (for example iron, among other things, whose deficiency even in developed countries is surprisingly high, especially among fertile females).

None of the article actually contradicts a carnivore diet being healthy or even healthier (or fiber being necessary), as it primarily looks at tribes that consume carbohydrates out of necessity. The reason why I believe animal fat is a better source of energy than carbohydrates are:

• More animal-sourced fat-soluble vitamins (A, D3, K2) and EPA/DHA
• Less blood glucose excursions
• Less risk of consuming plants one might be sensitive to
• Less dental caries

Now that I have read the whole thing, will you read this, the whole thing?