Steaks and other beef products are displayed for sale (file image)
Steaks and other beef products are displayed for sale at a store. (AP PHOTO)

Experts skewer claim that our ancestors only ate meat

David Williams February 24, 2023

For most of human history we have exclusively eaten meat.


False. A wide range of evidence shows our ancestors have never solely eaten meat.

An outspoken advocate of the carnivore diet claims we have exclusively eaten meat for most of human history.

Dr Anthony Chaffee made the claim in a clip of a podcast recording uploaded to Instagram (screenshot here) on February 5.

But the claim is false, with experts telling AAP FactCheck there’s no evidence to support the notion humans were not omnivores.

“If you look at our history for the last three million years we were only eating meat,” Dr Chaffee says in the Instagram video.

“If you can’t get everything you need from meat, then all these civilisations don’t exist and humans don’t exist.”

He then adds: “We have always been eating meat, and exclusively meat, and we have very good evidence of that with the stable isotope studies looking exactly what animals ate.”

A screenshot from the Instagram video.
 Dr Anthony Chaffee is a vocal advocate of the carnivore diet. 

When contacted for evidence to support the claim, Dr Chaffee told AAP FactCheck that “in many instances and for the vast majority of those millions of years we were only eating meat”.

However, he said he wasn’t trying to suggest there was no exception to the rule and was merely trying to point out “that meat clearly provided complete nutrition for humans seeing as we have in many instances past and present living generationally while exclusively eating meat”.

In reference to the Instagram post which was promoting the longer podcast, he said: “This was an isolated clip, taken out of context, and the full video should be viewed in order to see the full picture and understanding by anyone who is interested in this subject.”

The full podcast recording can be viewed here.

Dr Chaffee has made similar claims previously, including in this February 2022 YouTube video.

In alerting his viewers to an “Israeli study”, he said: “The term hyper carnivore gets used loosely now. That means you just eat 70 per cent of your calories are from meat … but no, this means that you did not eat plants, according to this study,” (video mark 2min 50sec).

The March 2021 study he refers to was carried out by researchers at Tel Aviv University. Dr Chaffee links to the same study in the comments attached to the podcast Instagram post, as well as to an April 2021 article about the study.

But the study doesn’t say our ancestors exclusively ate meat.

Sausages and bacon on a plate (file image)
 There is debate about the extent of meat eaten by humans, but no doubt plants were also included. 

Professor Matt Sponheimer, an expert in isotopic ecology at the University of Colorado Boulder, confirmed to AAP FactCheck the paper does not make the claim.

In particular he pointed to the following passage: “The assemblage of cases suggests that consumption of plants was common … we can summarize that the archaeological and ethnographic record shows that plant foods were a frequent component of the Paleolithic diet.”

Prof Sponheimer said the claim was “preposterous”.

“There is certainly debate amongst informed scholars as to the extent of animal food consumption, but anything approaching exclusive meat eating for any early member of the hominin lineage is contrary to existing evidence,” he said in an email.

Sireen El Zaatari, an expert in paleoanthropology at the University of Tuebingen, said the Israeli study assigned a maximum 70 per cent meat component in the diet of any species in human’s direct evolutionary line.

“They never conclude that there was a species in our lineage that was strictly carnivorous,” Dr Zaatari told AAP FactCheck by email.

In the Instagram video, Dr Chaffee backs up his claim by pointing to stable isotope studies. This YouTube video gives an explanation of the benefits of stable isotopes on understanding ancient diets.

A pile of meat (file image)
 Experts say there is no evidence to support the claim humans were exclusively carnivorous. 

But an expert in stable isotope analysis, Thomas Larsen of the Max Planck Institute of Geoanthropology, told AAP FactCheck that while the analysis provided valuable insights into past human diets, it was important to consider other lines of evidence and avoid over-generalising the results.

“The assertion that most hominin populations were exclusively carnivorous is not supported by the available evidence,” Dr Larsen said in an email.

Prof Sponheimer said the stable isotope evidence Dr Chaffee cited did not exist for anything prior to neanderthals and, while they probably ate a lot of meat, they did not live on it exclusively.

He said that as well as isotopes, early human diets could be determined from “trace elements, microfossils on teeth, use wear analysis of ancient tools to see what they were used to cut, analysis of archaeological bone and botanical remains … and our understanding of modern primates and their nutritional requirements”.

Julia Lee-Thorp, emeritus professor of archaeological science at Oxford University, said stable isotope studies don’t actually tell us about how much meat was in the diet.

“High nitrogen isotope values do not mean meat necessarily,” Professor Lee-Thorp told AAP FactCheck in an email.

“It’s got more to do with relative amounts of foods with high nitrogen isotope values (insects also fit the bill) and values for various foods can be variable depending on the environment. For hominin diets one plausible explanation is also insectivory. Insects are still eaten in large quantities today.”

Avocado and grapefruit salad (file image)
 You don’t win friends with salad, but fruit and vegetables have long been part of the human diet. 

Paleoanthropologist Briana Pobiner‘s research at the Smithsonian National Museum of Natural History centres on the evolution of the human diet.

She told AAP FactCheck the notion “humans ate exclusively meat for most of human history and prehistory is absolutely untrue”.

“This is the case whether we are talking about Homo sapiens (our species), or other species of the genus Homo,” Dr Pobiner said in an email.

The Verdict

The claim that for most of human history we have exclusively eaten meat is false.

While there is debate as to the extent of meat consumption in the diets of our ancestors, several experts told AAP FactCheck there is no evidence to suggest they ever exclusively ate meat.

This conclusion is mirrored by a study cited in defence of the claim.

False – The claim is inaccurate.

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