Once and for all, scientists have put to rest the theory that humanity’s ‘natural diet’ consists of soybeans and salads. The proof they’ve uncovered is — literally — set in stone.

Over the past few decades, the notion that humans are biologically suited to be vegetarians has gradually receded as an activist talking point. Proponents still insist that a plant-based diet is mankind’s “natural” diet, but there’s much greater traction these days in demonizing meat-eating as a nutritional and ecological disaster.

But in assessing the historical and physiological status of animal foods in human development and health, it’s important to cement the fact that physiologically speaking, animal foods are the appropriate fare for health and well-being.

Recently, yet another trove of historical evidence of humanity’s meat-eating origins was discovered in Israel.

As reported in Nature World News, a team of archaeologists from Tel Aviv University found what were described as ancient stone tools that revealed “prehistoric man’s taste for meat.”

The data were published in the journal PLOS ONE, a peer-reviewed, open-access resource from the Public Library of Science that includes scientific studies across multiple disciplines.

The discovery was at a site dating from the Lower Paleolithic Age, also known as the Old Stone Age, which archaeologists identify as extending from the beginning of human existence until about 12,000 years ago. The term Paleolithic, the source of the popular Paleo Diet, comes from the Greek words “palaios,” meaning old, and “lithos,” meaning stone.

According to the report, some 2.5 million years ago, humans survived on “a paltry diet of plants.” But as the human brain expanded, so did the need for greater nourishment. “So we turned to more substantial sustenance — namely fat and meat — to sustain it,” the researchers wrote.

Without the claws or fangs with which most carnivores come equipped, early humans developed the skills and tools necessary to hunt animals and butcher the meat from the carcasses.

Not to mention developing stone-tipped spears and other weapons, since those were the days when saber-tooth tigers and wooly mastodons roamed the Earth.

In their excavation, the team from Tel Aviv University found that the prehistoric stone tools they unearthed contained animal residue dating from 500,000 years ago. “These flint hand axes and stone scrapers still retained animal fat from long ago when humans cut into elephant remains, which were also found at the site,” the story stated.

“Archaeologists have until now only been able to suggest scenarios about the use and function of such tools,” Ran Barkai, the lead author of the study, explained in a statement. “It makes sense that these tools would be used to break down carcasses, but until evidence was uncovered to prove this, it remained just a theory.”

According to the researchers, this discovery represents the first direct proof of animal butchering with the use of flint tools as demonstrated by “use-wear analysis,” which involves examining the surfaces of stone tools to determine their function. Infrared residue analysis confirmed the presence of prehistoric organic compounds.

Here’s what’s even more interesting. After narrowing down the likely use of the stone axes and scrapers, the researchers actually conducted their own butchering experiment. As reported in Nature World News, “The team determined that the hand ax was prehistoric man’s so-called ‘Swiss army knife,’ capable of cutting and breaking down bone, tough sinew, and hide. The slimmer, more delicate scraper was used to separate fur and animal fat from muscle tissue.”

A total transition

So now we know beyond a doubt — not that there ever was much doubt about what “cavemen” actually ate — that prehistoric humans developed the anatomy and physiology we recognize as “human” on a diet of animal meat and fat. The question is why. Why did early humans switch from a “paltry diet of plants” to one that involved great effort and risk in hunting wild animals?

The answers are straightforward, according to the researchers.

“There are three parts to this puzzle: the expansion of the human brain, the shift to meat consumption, and the ability to develop sophisticated technology to meet the new biological demands,” the researchers said.

“The invention of stone technology was a major breakthrough in human evolution,” Barkai, the team leader, noted. “Fracturing rocks in order to butcher and cut animal meat represents a key biological and cultural milestone.”

None of us would consider a stone axhead to be “sophisticated technology,” but half a million years ago, it was the Google app of its day.

And a definitive milestone, not only for the earliest members of Homo sapiens, who catapulted tool-making technology into an evolutionary leap forward, but for us moderns, who can now state with assurance that animal foods are indeed our natural source of nourishment.

Accept no substitutes.

Dan Murphy is a food-industry journalist and commentator