“I feel by far the best when I eat only meat,” Fridman, a computer scientist, said during a 2023 episode of The Lex Fridman Podcast.

His guest that day was psychologist, author and fellow podcast host Jordan Peterson – also a carnivore – who credited the diet with having healed his chronic psoriasis and gum disease.

“I don’t like to talk about this much, because it’s so bloody radical, and I don’t like to propagate it, but this diet seems to have stopped all of that,” Peterson said on the show.

The paeans to meat have come after a 2017 appearance by Shawn Baker, a buff orthopedic surgeon, on hugely popular podcast The Joe Rogan Experience.

In an interview for this article, Baker said he had turned 50 the year before he went on Rogan’s show, a time when he was dissatisfied with his health, experiencing chronic knee pain and gut issues. Although he had recently shed 50 pounds by limiting his intake of carbohydrates and calories, he suffered from a general “I’m-getting-older” malaise.

Then he encountered “this crazy group of people online who were eating an all-meat diet,” he said. He decided to try it for 30 days, despite concerns that a person’s “colon would fall out from lack of fibre” on the regimen.

“I do the diet and feel fantastic,” said Baker, speaking by phone from his home in suburban Seattle. “And then I go back to my old low-carb diet and feel worse.”

“I get to eat stuff that only royalty would have eaten through history.”

Shawn Baker

He wrote about the diet that he had embraced – and also named, he said – in a 2018 book, The Carnivore Diet. This manner of eating had another surge in online popularity last June, when Rogan tried it and told his millions of listeners, “The best I ever felt – like, literally, the best I ever felt all throughout the day – was when I was on the carnivore diet.”

A plant-free, low-fibre diet goes against accepted views of what constitutes healthy, balanced eating, Linsenmeyer said. Meat and butter are “very high in saturated fat,” she said. “That increases the risk for cardiovascular disease. If this were my patient following this diet, I would be very concerned.”

There is also the matter of contributing to the warming climate, since meat and dairy production are linked to emissions of methane, a potent greenhouse gas.

Promoters of the carnivore diet argue that our ancestors subsisted on animals almost exclusively. Carnivorism, in their view, represents a return to a supposed hunter-gatherer golden age, long before the advent of highly processed foodstuffs.

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As a 2023 New Yorker article detailing the carnivore craze pointed out, however, studies of Neanderthals have turned up evidence that their diets included dates, tubers and other leafy foods in addition to meat. According to Herman Pontzer, an evolutionary anthropologist at Duke University quoted in the article, humans are “opportunistic omnivores” who will “eat whatever’s available, which is almost always a mix of plants and animals (and honey)“.

The New Yorker also noted a study by biologists David Raubenheimer and Stephen Simpson, who found that protein-loaded diets had a detrimental effect on animals’ life spans. “Our sexy, lean mice who ate high-protein, low-carb diets were the shortest lived of all,” the scientists wrote in 2014. “They made great-looking middle-aged corpses.”

Dan Buettner, an author who identified five regions around the world where people have especially long lifespans, said that a diet of predominantly whole food, plant-based meals, among other practices, is what leads to a long, healthy life.

“I know of no long-lived culture in the history of the world that were mainly meat eaters,” Buettner said by phone from Italy, where he was conducting further research on the places he has dubbed “blue zones.”

For some, going carnivore appears to be a facet of the optimisation culture that seeks self-improvement through so-called “biohacking” and other methods. For others, there may be an aspect of flexing one’s masculinity and success through the consumption of steak, a luxury in much of the world. It is notable that online promoters almost exclusively post videos eating red meat, though fish is part of the diet.

Baker, who planned to eat a rib-eye steak and 225 grams of salmon for his main meal on the day he was interviewed, said he kept two freezers in his garage, which at that moment contained “half a side of beef from a local rancher”.

Rib-eye steak, even when eaten every day, “is viscerally and primitively satisfying to me,” he said. “I get to eat stuff that only royalty would have eaten through history.”

Baker, who runs a nutrition and lifestyle company and no longer practices medicine, said he usually recommended that people adopt the carnivore diet for a limited time to reset their digestive systems. After that, they may reintroduce other foods or stay carnivore as he has.

“If somebody wants to turn it into a lifestyle and call themselves Carnivore Carl, that’s up to them,” he said.

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That people have embraced a way of eating referred to as “crazy” and “radical” even by its evangelists may say something about the Western diet of processed foods and its effect on the populace.

On this point, at least, Buettner can agree with the carnivores.

“We live in an environment where 95 out of 100 food decisions presented to us are bad,” he said. “So in desperation, to turn to an extreme diet, I don’t blame any overweight and unhealthy American.”

This article originally appeared in The New York Times.

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