'We've always been omnivores': Why 'meatfluencers' are wrong about what our ancestors ate

Paul Saladino is stripped to the waist, biceps bulging as he works a butcher's saw back and forth across a cow femur. When he finally severs the bone, a crowd of onlookers erupts in cheers. Flashing a smile, he checks to make sure he's being filmed, then scoops a spoonful of marrow from the center of one piece of bone. He then deposits it in the mouth of an eager young woman like a priest giving communion.

Saladino, a medical doctor, is a popular proponent of an animal-based diet that exalts meat and organs and demonizes vegetables. Through videos like this one on TikTok, as well as the podcast he hosts, he preaches the value of eating beef and liver, marrow and testicles to millions of followers on social media. He is the author of the 2020 book "The Carnivore Code" and a companion cookbook. He founded the company Heart and Soil, which sells organ-based supplements, and co-founded Lineage Provisions, which sells protein powder and meat sticks. Saladino contends that the traditional food pyramid, with its broad base of plant foods that narrows into animal foods, is upside down and that the medical establishment's view that high cholesterol causes heart disease is wrong. He says that meat and organs are the key to health, strength and vitality.

Saladino is not alone in his carnivorous pursuits. TikTok, Instagram and YouTube are teeming with influencers peddling meat-centric menus. Like the so-called paleo or caveman diets before them, these diets shun ultraprocessed foods such as potato chips, breakfast cereals, packaged breads, sodas and hot dogs. But they are significantly more restrictive than the paleo diet where plant foods are concerned. Some advocates, Saladino and celebrity adventurer Bear Grylls among them, allow for a limited amount of fruit but discourage vegetables, which they contend are loaded with defensive chemicals that are toxic to humans. Others, such as Canadian psychologist Jordan Peterson and his podcast host daughter, Mikhaila, champion a diet of beef, salt and water alone. Many, like social media personality Brian Johnson, aka Liver King, recommend consuming animal products — including dairy and eggs— raw.

Meatfluencers, as they are known, often charac­terize their regimens as "ancestral," made up of the foods our ancient predecessors ate. If this is what our ancestors ate, they argue, then this is what the human body is supposed to consume. "If you align your diet and Lifestyle with millions of years of human and hominid evolution," Saladino says in another TikTok appearance, "that is how humans thrive."

Studies of the remains of our forebears, as well as observations of living primates and modern-day hunter-gatherers, refute the idea that humans evolved to subsist primarily on animals. Meat did play a significant role in our evolution. Yet that doesn't mean we're meant to eat like lions. Real ancestral human diets are difficult to reconstruct precisely, but they were vastly more varied than the mostly meat diets of carnivores, a finding that has important implications for what people today should eat to be healthy.

To be fair to the promoters of flesh-forward diets, scientists have traditionally paid a lot of attention to meat eating in human evolution, as have journalists who write about our origins (including me). Several factors have contributed to this trend. For one thing, we humans are unique among primates in regularly hunting Animals that are as large as or larger than ourselves, and scientists are particularly interested in understanding traits that set us apart from other creatures. For another, stone tools and butchered animal bones are more readily preserved in the archaeological record than fragile plant remains. And then there's the fact that the hunting of Animals — particularly large, dangerous maMMAls such as elephants — is inherently more exciting than the quiet Business of gathering berries, nuts and tubers. In any case, it doesn't take a lot of googling to turn up a heap of scientific papers and popular articles touting the idea that hunting and eating meat made us human.

Interest in the role of meat and hunting in human origins has deep roots. Charles Darwin even speculated about its importance in his 1871 treatise, The Descent of Man, and Selection in Relation to Sex. Ideas about how carnivory shaped human evolution have shifted over the years, but the prevailing wisdom is this: around two million years ago Homo erectus, an early member of our genus, began evolving modern human body proportions, with longer legs, shorter arms, a smaller gut and a larger brain. The earliest stone tools and animal bones bearing cut marks date to before that period. The timing suggests that the invention of sharp-edged stone tools allowed early humans to butcher large animals and have access to a rich new source of calories. This nutritious food required less processing in the gastrointestinal tract, which allowed our energetically expensive gut tissue to shrink. Calorie-dense meat also provided fuel that allowed our energetically expensive brains to expand. A feedback loop took hold: as brains ballooned, our increasingly clever ancestors dreamed up ever more effective tools for procuring energy-rich animal foods, fueling more brain growth in Homo.