Even Our Ancestors Never Really Ate the “Paleo Diet”

By Guest Blogger | June 3, 2013 2:32 pm

By Carrie Arnold

Despite its name, the Paleo Diet is a new food trend, one which has become increasingly popular in recent years. The diet’s basic tenet is that our bodies haven’t yet evolved to cope with the changes to our food intake as a result of agriculture. Paleo Diet aficionados hold that grains like wheat are making us fat and unhealthy, and that we would be far better off if we ate how our ancient ancestors did, focusing on lean meats, fruits and vegetables.

What researchers haven’t been able to answer, however, is exactly what our ancestors ate. Early humans and our other hominin predecessors lived pretty much everywhere, in environments as diverse as the Arctic, tropical rainforests and deserts, and so its likely that diet varied by region. Even within a given region, reconstructions of diet have had to rely on tooth analysis or bones found nearby.

A quartet of papers published today in Proceedings of the National Academy of Sciences have instead turned to stable isotope analysis, which analyzes the specific chemical signature of molecules, to determine the diets of a variety of ancient hominin species by looking at their fossilized teeth. The findings show that human ancestors started moving away from the traditional ape diet of fruit and leaves about 2.5 million years ago—much earlier than previously thought. Thus, even our “paleo” ancestors may never have eaten a paleo diet.

(For more paleo myths, read our April article “Paleomythic.“)

“Most modern primates have diets of leaves from trees and shrubs. What sets humans apart is their transition to the new restaurant in town,” which serves grains, grasses and sedges, said Thure Cerling, a geologist at the University of Utah and co-author of three of the four new PNAS papers. “Humans are one of the few primates to figure out how to access this resource, which they appeared to do sometime between 4 and 3.5 million years ago.”

Carbon clues

Researchers frequently analyze carbon’s chemical signature when they study organisms, living and dead, since carbon is a key component of the molecules of life. Unlike radioactive isotopes, stable isotopes don’t radioactively decay, which means their ratios remain constant over time.

Carbon has two stable isotopes: carbon-12 and carbon-13. Most of the carbon found on Earth is carbon-12, which means it has six protons and six electrons. Stable isotope expert Hope Jahren, a geologist at the University of Hawaii who was not involved in the studies, calls this vanilla carbon. Carbon-13, which makes up just 1.1% of Earth’s carbon, has six protons and seven neutrons. Jahren calls this cinnamon carbon.

Stable isotope analysis essentially measures the ratio of vanilla and cinnamon carbon, Jahren says. It’s useful because different organisms have different ratios depending on what they eat. Plants have different ratios of vanilla and cinnamon carbon based on the type of photosynthesis they use. Plants using C3 photosynthesis (trees, shrubs and herbs) aren’t picky about whether they use vanilla or cinnamon carbon, so the ratios in these plants are the same as the ratio of carbons in the natural environment. Plants that rely on C4/CAM photosynthesis (including tropical grasses and sedges) are much more selective toward cinnamon carbon. Since animals build molecules in their bodies from the foods they eat, analyzing the stable isotopes of fossilized remains can tell scientists a lot about an ancient organism’s diet.

“Your bones are not just made of the last meal you had, but the meals that you’ve had across many years. By looking at the composition of those teeth, researchers can say that something was a large component of the diet. This tells us a lot about how hominins lived and what they ate,” Jahren said.

Great grains

Essentially all of the great apes and their ancestors appeared to have eaten a C3-based diet, consuming fruits, leaves and other plants. Modern humans, on the other hand, rely much more on C4 plants, which include grains like wheat sorghum and corn. What researchers didn’t know was when that shift occurred. The PNAS papers show that this shift appears to have occurred in Australopithecus afarensis, which lived in and around Ethiopia 2.9 to 3.9 million years ago.

An analysis of the vanilla and cinnamon carbon in A. afarensis from the middle Pliocene (3.0 to 3.7 million years ago) shows that this hominin had already shifted to a C4-based diet. Jonathan Wynn, a geologist at the University of South Florida, and colleagues analyzed 20 fossilized teeth of A. afarensis from the Hadar region of Ethiopia. Although there was significant variability in the proportion of C4 plants consumed, on average, A. afarensis consumed significantly more C4 plants than its recent ancestor Australopithecus anamensis. These hominins were thus already eating grain in an adaptation for life on the savannah, Cerling said.

Cerling’s own analysis of hominin fossils found in the Turkana basin in Kenya, and published in a second paper, shows that some hominins there were also making the shift to a C4-based diet. Several species of Homo (the authors did not distinguish between several of these closely related species) as well as Paranthropus boisei, which lived between 2.3 to 1.2 million years ago, showed evidence of a grain- and grass-based diet. This shift coincided with the retreat of heavily forested areas that were replaced by open savannah.

A third study, also led by Cerling, used stable isotopes to analyze the diet of several species of Theropithecus, the ancestors of the modern gelada baboon, a grass-eating ape that lives in the highlands of Ethiopia. Like its descendant, Cerling and colleagues found that the ancient Theropithecus species almost exclusively ate C4 plants, similar to the diets of the modern geladas. But although ancient Theropithecus and ancient hominins lived in the same area and both had a primarily C4 diet, they did not appear to be in direct competition with each other, Cerling noted, likely because they preferred different types of C4 plants.

A new hominin trait

Finally, a review paper by Wynn, Cerling and colleagues analyzed what we know about ancient hominin diets. Big brains and upright walking are two of the main factors that distinguish humans from other primates, and it appears that a shift in diet from leaves to grasses may be a significant third factor.

“Hominins began leaving the forests along the riverbanks and venturing more and more into open habitats that primates haven’t previously explored,” Cerling said. “Most primates today are still stuck in the forests.” Human success, he noted, is partly linked to our ability to exploit a more diverse array of food.

“These studies are important mainly for their novelty,” Jahren said. “It’s a major advance in understanding not just what a hominin looked like or where they lived but what it was like to be one—how they lived, what they sat down to eat every night if they were lucky. That’s a major advance.”

So while there remains little doubt that many modern humans eat too much sugar and processed foods, these studies show that identifying a particular “paleo” diet is impossible. Researchers are just beginning to understand what ancient humans ate, and these recent studies show that grasses and grains have been part of the human diet for millions of years.

Carrie Arnold is a freelance science writer in Virginia. She blogs about the science of eating disorders at www.edbites.com, and frequently covers microbiology topics for national magazines.

Image by dctim1 via Flickr

CATEGORIZED UNDER: Health & Medicine, Top Posts
  • Alice Parker

    But the grains were whole grains and were sparse, not like eating a box of wheat thins at one sitting. Refined grains that are immediately accessible (check out the food available at the local minimart) dominates our snacking, along with refined sugar, and corn syrup refined from corn. Avoiding refined flour and sugar has improved my health!

    • cory

      Actually, the fertile crescent was called that for a reason. In 1967, using bone sickles, Harlan found that a family could harvest more than enough wild emmer wheat and barley for a year within a 3 week period (Harlan, Jack R. “A wild wheat harvest in Turkey.” Archaeology 20.3 (1967): 197-201.)

      . Recent studies (Kislev, Mordechai E., Ehud Weiss, and Anat Hartmann.
      “Impetus for sowing and the beginning of agriculture: ground collecting
      of wild cereals.” Proceedings of the National Academy of Sciences of the United States of America 101.9 (2004): 2692-2695.) not only back up that experiment, but show that sickle harvesting may not have been necessary, as adequate supplies of wild grains could have been simply picked up off of the ground.

      I enjoy a low-carb paleo-style diet. I just wish it was named more accurately.

      • http://www.facebook.com/txomin.da Da Txomin

        Yes! Thank you. Agriculture was never necessary. Everything just grows around on its own in infinite amounts…

        • Agnes Debinski

          Agriculture as such was one of the best human inventions. But do healthy people actually need diets? I don´t think so. Incidentally, nobody is obliged to agree with me.

      • Agnes Debinski

        Cereals are certainly very healthy. But many people want to eat all sorts of other healthy & even tasty products too.

      • Isabel Marissa

        There is no doubt that paleo diets are extremely effective as i’ve lost around 65 lbs in about a year and half. However, I really can’t emphasise the importance on getting a sustainable long term paleo diet plan that is not gonna have bad effects on your health. The best paleo diet cookbook (with planned diet regimes) I found is newsciencediet*com/paleo (obviously change the * to a dot as it wont let me post links here) and would highly recommend it to anyone looking to paleo diet!


        • guruurug

          Losing weight is a simple matter of eating less calories, the diet has zip to do with it.

    • primalcat

      exactly. Also, humans can survive on grain/legume diets, they just don’t tend to thrive.

      • Kyle Key

        I’d love to see the scientific evidence for this claim.

        • Martin351

          Look at good ole Dr John McDougall, or should I say “Dr I’m on my death bed Mcdougall”. He practices and preaches that very diet and the poor guy is pale, sick, pile of insomnia with half the energy the average person.

          Unfortunately the best scientific evidence is actual experience for those that follow it long term. You won’t find one person in the world who follows a strict grain/legume diet that is healthy when they reach their later years. That is a concrete fact.

          • Kyle Key

            No thanks, I asked for the scientific evidence, not biased opinions.

      • Agnes Debinski

        That´s so true. I honestly believe we are better off eating eggs and meat as well.

      • guruurug

        There are people who thrive off eating fast food.

    • agnes debinski

      Whole grains including huge amounts of sugar really are far from healthy, especially if eaten on an empty stomach. I do agree with your point of view.

    • Agnes Debinski

      Whole grains are very nutritious, while food with added sugar is probably very easy to eat as they are perceived as tasty, but already kids at primary school are at risking of getting diabetis because of the constant intake of sugar-loaded snacks and so I fully understand concerns in regard to that matter. (I feel obliged to add that we are speaking of artificial sugar.)

      • Kruntz

        The glycemic index for whole grain bread is not much different from white bread. They both have an high glycemic index. Whole grains can be dangerous to those with insulin resistance. Also, more evidence is showing that celiac disease is just one manifestation of gluten intolerance and that as much as 30% of the population release antibodies that attempt to fight off gluten as an unwelcomed food. There is also plenty of scientific data that document additional issues with grains as well.

    • Jack Young

      do you also avoid animal fats?

  • Alexa

    Also, the big agri-grains we eat today bear little resemblance to what our ancestors, or indeed our great grandmothers, would have been eating.

    • primalcat

      Absolutely right.

      • George Henderson

        Not only that, but compare a loaf of bread from 100 years ago (high extraction flour, salt, malt, yeast) with those available today (low extraction grains, soy protein, milk solids, extra gluten, vegetable oil, sugar or HFCS, added B vitamins and iron, etc.). It is not the same food at all, and not something that ever existed before.

    • Hannah

      I believe this is a very good point. Also the article seems to not show a distinction between the state of the grain when it was consumed. I assume that it was raw grains and not the engineered grain product, bread, that we eat today that is much more concentrated.

      • Kruntz

        It doesnt matter anyway because the claims about our ancestors eating grain are not proven. The four papers that this article refers to do not draw the conclusion that our ancestors diets included grain. It is also a possibility that the diet of what our ancestors ate included grain. None of the four articles came to the same conclusion as this author did. Carrie Arnold has no idea what she is talking about.

    • sb

      Also, neither do the sources of animal proteins.

      • Schitso

        Not sure about you, but the animals I eat are raised in exactly the same way that my grandparents and their grandparents raised them.

    • Nicolae Carpathia

      Neither do the fruits and leafy vegetables. They’ve all been domesticated. Everything has been domesticated, because by definition that’s what sells.

  • Chuck Charbeneau

    Paleo information [needs citation]. While there’s some for your other points, your premise appears to be lacking any… hrm.

    Did you ask to interview Robb Wolf, Chris Kresser, Matt Lalonde, Dr. Cordain? Did you read any of their actual published research, or did you look at a couple of hype pieces and draw your own conclusions about Paleo?


    • Stefan Parol

      You complaing about missing facts, and in a way state the author would only present “factoids” with no actual proven relation. Having read the article, I can not follow this argumentation. In fact, I feel it is you who laks in delivering any reason for doubting the stated conclusions. Indeed, have you yourself read the aformentioned publications?

      “Paleo information [needs citation]. While there’s some for your other points, your premise appears to be lacking any… hrm.”

      • Chuck Charbeneau

        Yes really.

        My point was that the author cites paper after paper to support her claim and yet doesn’t show where the Paleo Literature hasn’t either supported it’s claim or retracted or changed it’s premise based on new and emerging data.

        There’s no support that this is actually what the proponents of the Paleo currently support or believe.

        But, sure.

        I’m not here to do her work for her.

        Feel free to read Cordain, Wolf, Hartwig [et al.], Kresser, Lalonde. All of their work is founded on good science and well cited.

        • Stefan Parol

          This is an articele, not a scientific work, in wich case I surly also would demand sources.
          Also, the author presents lots of sources and quotes. So if you are unsatisfied with given information and feel, as you do, like to somehow imply possible incorrect conclusions, it is your turn to prove it. Fair enough.

        • George Henderson

          Yes, no-one believes in “lean meat” anymore, our ancestors were fond of bone marrow and brains.

        • Andrew Kiener

          So are you arguin that the author’s very brief description of the paleo diet is so completely inaccurate that the research into when we began eating grains is irrelevant? Or are you suggesting that there are recent revisions to the ideas behind the paleo diet that account for the flawed history and science in the original concept?

  • Ray Audette

    Raw grain is not edible to Humans!

    • Stefan Parol

      Promoting one`s own work with the work of someone else is just weak. Write your own blog or avoid advertising.
      Also, if your point is, as I take it, that humans would not be able to digest raw grain, it is simply wrong.

      • Canadian Girl

        Stefan you seem to be a hater of anyone who disagrees with this article. You do realize that this is an open blog right? And since you like to point flaws in other peoples responses why don’t you elaborate on “it is simply wrong” … try backing up your work if your’re going to be a critic 😛

  • Matt Keehan

    I’m a little confused here; humans can’t digest cellulose. I previously understood that finding evidence of grasses in human remains via isotope analysis was taken as proof that our ancestors ‘ate the animals that ate the grasses’. Is that not the case?

    If not, wouldn’t the presence of c4 in such early ancestors suggest that they differed from us, in being able to digest it, like our close primate relatives do?

    • George Henderson

      Or, that they ate animals which had incorporated C4 from grasses into their own bodies?

  • primalcat

    The current idea of a paleo diet would fit the foods in most areas, it just means animal protein (meat, eggs, fish, pork, fowl, insects, etc.) and plants (fruit, vegetables, nuts, seeds). So even though humans lived in many different parts of the world, it doesn’t matter where on Earth the people were, they would still have eaten what is popularly being called the paleo diet.

  • Brian Mason

    Actually, not really a “New Diet”. Bodybuilders have been following this “Diet” to trim down for shows since the 1950’s. Although it wasn’t called anything. There was not much science behind it either. They just used trial and error and found something that worked for them. The thinking is, when trying to lose body fat and keep the muscle you gained, reducing your intake of carbohydrates would cause your body to use your existing fat storage as fuel, therefore burning the fat as its used but keeping most of the muscle because your protein intake would stay the same. In this preparation for the show, at every meal (which could be about 6 a day) you would intake a Protein to feed your muscles and vegetables for fiber, to aid in digestion. Grains and Sugars are carbohydrates that your body consumes slowly. Most of us intake more carbohydrates than our bodies use and there for our bodies store it as fat.

    • Trial Error

      It was mainly so the body was depleted of gylcogen and gave up water and made the muscles more defined. Fat was lost before this over periods of months – not typically eating low carb.

  • Brian Mason

    Your body also uses Fats and Oils as fuel, which are consumed at a faster rate than Carbohydrates. Therefore, your body will store less of it as its consumed.

  • George Henderson

    Wouldn’t animals that ate C4 carbon plants supply C4 carbon?

  • symbiont

    What they forget is that its silly to assume that just because a particular group of our ancestors show signs of grain consumption then this means humans should still consume it. Finding a fossil is like winning the lottery, and NOTHING fossilizes in the tropical forests- where we mostly evolved. So to assume that what these fossilized ancestors OUTSIDE of the forest is what ALL humans eat is utterly ridiculous. Its merely a snapshot of what one particular group that had separated from the main group ate at one particular time. The forest was drying up, and so it was a SURVIVAL diet.

    The correlation between fruit/vegetable consumption and intelligent brains across many species is very very good. Look into the work of people like Tony Wright who wrote the book Left In The Dark

    • Andrew Kiener

      What you forget is that humans have been eating grains very successfully for all of recorded history and for all of the known prehistory during which we could be called “humans”. Claims that something so common for so long has suddenly been found to be harmful require evidence strong enough to counter that, and so far nothing has turned up.

      • heinrich6666

        What you forget is that ‘success’ has different meanings depending on whether the perspective you choose is that of the individual or the species. Agriculture has been supremely successful in feeding perhaps billions of people who perhaps would never have been fed otherwise. So from the point of view of the species, it has been great. But it’s also possible that the tendency toward the overconsumption of carbohydrates enabled by agriculture can be harmful at an individual level.

  • heinrich6666

    So in the concluding paragraph we have “identifying a particular “paleo” diet is impossible”. Then “Researchers are just beginning to understand what ancient humans ate”. No contradiction there?

    • Andrew Kiener

      No, no contradiction. The second statement explains the first.

      • heinrich6666

        Nice try. If it were impossible, researchers would be wholly unable to understand what they ate, no? So why do they even try? I’m sure that the veiled point here is that any ‘paleo’ diet, however reasonable, is wrong by default — that is, until the scientific mainstream gives it its imprimatur.

        • amphiox

          They key word is “particular”. There is no “particular” paleo diet that is possible to identify. Our ancestors ate a wide range of different diets, depending on where and when they lived, among other things.

          • heinrich6666

            Your own assertion is different than the author’s. I would guess that the scientists doing the research act with the understanding that it’s *very* possible to learn about this or that particular diet.

    • d1stewart

      Well, not that it’s historical, but try identifying a particular paleo diet today. What any one paleo diet guru says not to eat, some other paleo guru says is okay. Take any food that is non-paleo in one guru, and put “recipe for paleo —-” in front of it in Google, and you’ll find a recipe for it (usually with someone’s non-paleo ingredients). “Paleo red velvet cupcake.” “Paleo ice cream.” “Paleo taboulleh.”

      Yes, identifying a particular paleo diet is impossible.

      • heinrich6666

        There’s no doubt that faddishness drives paleo diet book sales, and different authors want to put their own spin on it to stand out in the marketplace. But different “paleo” diets have been identified already. The traditional Inuit diet counts as a “paleo” diet inasmuch as it is rich in Omega-3, is absent wheat, etc., etc. That diet has been eaten up till today or, at least, until very recently. So your point that just because you can find “paleo ice cream” recipes online means there’s no such thing as traditional non-agricultural diets is, well, nonsense.

        • d1stewart

          If I had said “there’s no such thing as traditional non-agricultural diets,” you might say that was nonsense. As it is, your saying that my point is nonsense is nonsense. I didn’t say that, and it wasn’t my point.

          There are a few traditional non-agricultural diets. They are the diets of people in extreme conditions and among peoples who also undertake extreme activities due to their environments.

          That these traditional non-agricultural diets are non-atherogenic, non-teratogenic, and model diets for even the people who consume them, let alone western people, is the nonsense.

          • heinrich6666

            You seem to be confused then. The more credible of the so-called paleo diets simply call for a diet more in line with what can be inferred about pre-agricultural eating habits. They stress ketosis, the importance of Omega-3, etc. Thus the ‘paleo diet’ is more a set of principles than a laundry list of specific foods. But that is hardly a weakness, and hardly justifies saying ‘identifying a paleo diet is impossible’.

            As for your other comments, they’re highly arguable. Your claim for example that traditional diets are teratogenic is bizarre. Your claim that there is some homogeneous group called ‘Western people’ with a single diet that is appropriate for them (as long as it isn’t ‘paleo’ you’re likely to approve) is nonsense given the overwhelming diversity of ethnic groups and physiologies among people in the ‘West’.

  • George Henderson

    “The isotope method cannot distinguish what parts of grasses and sedges human ancestors ate – leaves, stems, seeds and-or underground storage organs such as roots or rhizomes. The method also can’t determine when human ancestors began getting much of their grass by eating grass-eating insects or meat from grazing animals.”

    Or, for that matter, by eating honey produced from grass pollen.

    Also, these C4 grassy foods EXCLUDE most modern grains: “C3 plants include trees, bushes and shrubs, and their leaves and fruits; most vegetables; cool-season grasses and grains such as timothy, alfalfa, wheat, oats, barley and rice; soybeans; non-grassy herbs and forbs.”

  • Julian Skinner

    All this study shows is that C4 plants were eaten millions of years ago. So C4 plants include grains and grasses- they also include “About 7600 species of plants use C4 carbon fixation, which represents about 3% of all terrestrial species of plants”

    Nonsense to suggest that because C4 plants were eaten that means grains were eaten. There is simply no evidence for that.

    some traces of fern root were found on grinding stones 30000 years old, but for grains you have to wait for the neolithic 10 000 to 12000 years ago.

  • Susan Durham

    Sorry, that’s baloney. Unless they were eating “grains” without cooking them, because the earliest campfires are only 2.5 million years old. So, as usual, y’all have failed to “debunk” anything, except your own credentials for debunking anything.

  • Ryan

    The author is confused as to which plants actually use C3 vs C4 photosynthesis. Wheat along with most other grains except corn use C3 not C4 as she stated. Also, the tests
    were done on hominids that were not even our direct ancestors . A.
    afarensis was a dead end. But so what I’ll play the author’s game.
    Lets pretend she got her facts straight and used relevant data. I
    would conclude that the reason we see start to see higher ratios of
    C4 to C3 in our ancestors fossilized teeth around 3 to 2.5 million
    years ago is because that is when we moved out of the jungle and
    started hunting and eating the big game animals that grazed off of
    the C4 grasses and seges of the savanna. *Derp* Yes C4 and C3
    isotopes are also absorbed indirectly through animal meat.

  • http://blogs.discovermagazine.com Ian Ward

    It’s too bad humans didn’t evolve to live off carbon dioxide and water like plants: then we would all be able to be hypersomniacs like the girl in the July Discover magazine article.

  • http://blogs.discovermagazine.com Sky King

    Why hasn’t anyone postulated the possibility of our early ancestors getting their grains from eating the entrails of animals, which possibly contained at the time of consumption digested and undigested grains/grasses.

    From what I’ve read….this was actually considered a prized delicacy and was given to the person who actually killed the animal.

    • d1stewart

      I’d love to see the research support for this ritual of giving the filled intestines to the person who killed the animal. If this was a delicacy and a ritual, then how would anyone but the occasionally successful hunter get their grains? (Killing the animal is, of course, challenging, since they do resist killing and some research indicates only about 1 in 30 hunts had success. Which means that usually the women gathered carbohydrate-rich foods for virtually every meal, while the men went out doing the manly hunting and failing to kill anything to put on the fire.)

  • http://twitter.com/BlackwoodYmail julie blackwood

    Today being vegan is the sane and compassionate choice.

  • Guest

    All I know for sure is that eating low-carb, paleo-style, makes my body feel better and look better. I have never been fat per se, but relatives who haven’t seen me for a while are amazed that my body is shaped like it is at my age. It is flattering and a little strange, and I’m not going to let go of the Paleo that makes it that way.

    • Andrew Kiener

      No one says to let go of it if it works for you. Different people have different metabolic needs. Just don’t go on thinking that the misunderstanding of evo history it’s based on makes sense.

  • Larry Olson

    All I know for sure is that eating Paleo makes me feel better and look better. I’ve never been fat per se, but relatives who haven’t seen me for a long time are amazed that my body is shaped like it is at my age. It is flattering and kind of strange, and I will continue eating Paleo to keep it that way.

    • LiveFreeOrDiet

      I was very fat: 55.5 BMI. Not that I knew it as “Paleo” but I lost 125 pounds in 8 months and have kept it off for 9 years, all without having to be hungry. I eat more now than back when I was gaining weight.
      And anyone who tries to say it’s because I’m bored needs to try my dinner tonight: charcoal-grilled tri-tip steak, brussel sprouts in butter sauce and fresh tomatoes, then strawberries with lots of fresh-made heavy whipped cream and real vanilla for dessert!

      • Jack Young

        what was your plant/meat ratio?

        • LiveFreeOrDiet

          I tend to eat a lot of vegetables. I would guess vegetables to meat is 2:1 by volume. The ratio is according to what I want to eat as much as anything. Really, I just avoid (in order of worst to best) alcohol, soda & juice, candy, sweets, grains (especially white flour) and starchy vegetables. I eat some kind of fruit every day as my dessert.
          BTW, I initially tried the Atkins Essentials book’s “Induction Phase” goal of 20 grams of “net carbs” (total carbs minus fiber), but that was too low for me. I feel much better above 40g. When I track it, I find I naturally eat between 50g and 100g.

  • tkent26

    You what else would have a stable isotope signature very similar to grasses? The flesh and organ meats of ruminants. So…alternative hypothesis: early hominids started eating more ruminants around the time of these fossils, through hunting, scavenging, or both. Has anyone tried eating wild grasses? Indigestible for most mammals, unless you have the stomach(s) and gut flora of ruminant. On the other hand, the flesh of wild ruminants would be digestible, full of bioavailable nutrients, and could provide the nutitional boost to power the evolution of those big brains.

  • Mike Kaeser

    Isotopes are protons and neutrons, NOT protons and electrons.

  • xmichaelx

    “Paleo” diets just remove processed food. Not sure why that’s so hard for people (like this author) to understand, or why people (like this author) find it such an offensive concept.

    • Andrew Kiener

      There’s a lot of fake-science handwaving in the paleo movement. It’s that part that bothers people.

      • heinrich6666

        This article is itself partly to blame. It’s dressed up as a smug attack on the ‘paleo’ diet craze, and even frames the research it’s reporting on in those terms. But the research has nothing to do with anatomically modern humans or the much more recent emergence of agriculture. The conclusions of the research are quite limited: our ancestors 2-4 million years ago stopped eating fruit and leaves. It doesn’t touch the assertions of the ‘paleo’ diet’s many proponents. Yet, here is a blog attached to Discover magazine making this tenuous connection. One has to ask: why?

        • Nono_Yobiz

          Move goalposts much? One of the major tenets of paleo dieters is that grains are a recent introduction through modern agriculture. This research clearly shows that we’ve been eating grains for literally millions of years.

          • heinrich6666

            Ignore the goalposts much? This research ‘clearly shows’ that a class of plants (C4) was a part of the diet of our distant ancestors. You’ll note that in the article above, the word ‘wheat’ is now crossed out. It seems that wheat is not among the C4 class of plants (though the author originally thought it was). And yet, wheat is generally what we’re talking about when we talk about agriculture. So does this research strike down the Paleo perspective? Certainly, not. Especially since no Paleo that I know of is ‘meat-only’, and since today’s post-agricultural diet bears essentially no resemblance to the C4-inclusive one sketched out by this research.

          • Kyle Key

            Yeah, wheat is crossed off because it’s a C3 plant. “Essentially all of the great apes and their ancestors appeared to have eaten a C3-based diet, consuming fruits, leaves and other plants.”
            It’s not up for debate that our ancestors were eating C3 plants for millions of years.

          • heinrich6666

            Yeah, your comment flirts with being totally irrelevant. The tries to pinpoint the shift from C3 to C4 in dietary preference of early hominins. What’s up for debate is precisely everything — namely, what the bearing of this research has on understanding the dietary needs of anatomically modern humans. Personally, I think extrapolating from this research at this stage would be pretty irresponsible — because the link is tenuous and much more research is needed. But the article does so anyway, choosing to frame the research as proof the so-called paleo diet is bunk. So there you are.

  • Larry Olson

    I think it just irritates a few people that some Paleo adherents like to overdo a good thing and push the edge of the envelope into silliness. The guys that publish recipes for stone bowls of gizzards and offal, preferable eaten in a crouched position. So they want to shoot down their bs

    Personally, I don’t see how these grains would have contributed much to anyone’s diet outside that corner of the fertile crescent. Some prey animals eat grass. Most humans just wouldn’t have access to a lot of daily carbs. It would have been a binge food for many troupes, when fruits ripen.

    Kids have an extra strong taste for sugar. I imagine they ran around supplementing their own diets with berries and fruit, while the adults in most parts of the world would not have much daily carb access. And so we see how kids can remain quite thin with a bag of candy in their daily diet. Adults, not so. I think Paleo ideas have it mostly right, it’s just necessary to understand that some regions supplied different mixes, as the article points up.

  • http://www.facebook.com/txomin.da Da Txomin

    Another debunking of a description of Paleo that suits the author. In other words, useless. Pity. Plenty is wrong with Paleo but I have yet to read a single honest review.

  • agnes debinski

    I wouldn´t presume, that any natural meal is the cause of
    people being unhealthy (as long as the food we are referring to isn´t poisonous – such as poisonous mushrooms e.g.). The way I see it – thus I do share the point of view of the author of this article – artificially generated food, such as chocolate and candy, are a threat to people´s health – if eaten in huge amounts – and not our daily porridge. The truth about natural food is – regardless of whether we are talking about fruits, vegetables, or wholegrain meals or even natural fats such as olive oil – that it is being digested entirely instead of being turned into fat cells on your body and toxins in your blood, which is exactly what ice cream will do to you, if eaten on a regular basis. All sorts of sweets such as candy, chocolate and so forth are also considered a threat to the health of human bodies, if eaten often and in large amounts, as neither our descendants, nor we are capable of breaking down this kind of food, and so we humans end up storing “sweet toxins“ (toxins produced due to having eaten artificially produced sweets, as opposed to natural sweets, such as the sugar within apples) in our blood, until our blood cleans itself from these toxins, which it can only do, if we change our diets, or in other words, either give up on the intake of sweets altogether or cut down our consumption of sweets to an almost nonexistent degree.

  • chatpaltam o

    gosh i hope my ancestors did not look like that photo either

  • Larry

    So how old is McDonalds? 2 to 3 million years?

    Only a bunch of Apes would come up with this crap.

    If there is such diversity in nature, why the Hell do you Apes deny the fact that man is NOT a primate.

    Those who build the pyramids were far advanced in many fields, than modern man.

  • George

    You can scavenge a lot if you are bigger or more numerous or bolder than the animal that made the kill, or if you are diurnal and scavenging from a predator that is nocturnal. Man is a born thief. This chap was a very distant ancestor, but if he was a scavenger he was not the raw food vegan this author thinks he was.

    • Nono_Yobiz

      Even fully modern human hunter-gatherers get the majority of their calories from gathering. See the fieldwork of Lee, Harpending, Draper etc. with the Dobe !Kung. Afarensis and Habilis weighed 90 lbs and stood not much over 4 feet. They were third tier scavengers and leopard prey. By daylight, after the hyenas and wild dogs were finished with the kill, our ancesters were left with furtively picking over tendons and cracking bones while worrying about the predator or higher tier scavengers returning and killing him.

      • George

        Firstly, Afarensis is not a paleolithic human but a much earlier hominid, so nothing about Afarensis can refute a “paleolithic” argument. That paleolithic man, with his stone tools and control of fire, was an effective predator is shown by the extinctions of large animals – predators and prey – that accompany his migrations.
        Secondly, gathering includes animal foods such as eggs, reptiles, honey, insects, shellfish.
        Thirdly, the Dobe !Kung live in a desert. They are left in peace because their land is least fertile. This is true to some extent of almost all modern hunter-gatherers (with the possible exception of the Andamanese, who enjoy a diet rich in pig, turtle and honey). Those in the historical record are often noted by explorers as hunters and meat-eaters, but the herds they relied on have been slaughtered and the tribes displaced, precisely because they lived on land that supported such food.


    Carrie Arnold, according to intros of the first two PNAS articles you sighted, can one distinguish between a diet inclusive of C4 plants, and a diet inclusive of animals which themselves have diets inclusive of C4 plants?

  • Stagester

    The reason people are turning to the Paleo-diet is its benefits not its historical accuracy. Wheat and other grains have built in anti-nutrients that are making us sick. That’s why.

  • Alyssa Copeland

    Actually C4 plants do not discriminate between 12C and 13C due to storing them in the bundle sheaths for photosynthesis. C3 plants discriminate against 13C and are more selective… they tend to choose 12C over 13C.

    Grasslands and C4 plants were widespread by late early Miocene and had ecological dominance by 7-11 MYA. So grains were very abundant to eat

  • sa

    What all of these articles fail to mention is the link between control of a small group of humans over the majority through ORGANIZED RE-LI-GI-ON and the link between that and agragarian societies. Eating grown and harvested wheat products is DIRECTLY the result of this link. You’ve got to feed all of your (brainwashed) followers, right? (Be fruitful, and multiply?) I’m going to break it down: WHEAT IS BAD FOR YOU. SOY IS BAD FOR YOU. LEGUMES ARE BAD FOR YOU. NOT-EATING-MEAT IS BAD FOR YOU. YOU SHOULD NOT BE CONSUMING ANOTHER ANIMALS MILK AS A NEED. THAT IS ALL (idiots).

  • The Vegetarian Site

    Want longevity? Then follow the traditional Okinawan diet or the American 7th Day Adventist vegetarian diet. Both groups consume very little animal products/byproducts. They do consume plenty of whole, plant-based foods (and legumes too!)

    • Martin351

      My gf’s family is from Okinawa and follow a traditional diet. It doesn’t include legumes and it’s about 60% plant foods and 40% meats.

      Don’t make false assumptions. What you said is completely wrong.

      • The Vegetarian Site

        The diet of your gf is irrelevant. The fact that the traditional Okinawan diet associated with longevity is almost entirely plant-based is detailed in many peer-reviewed journal studies, e.g. Hiroko Sho (2001). “History and characteristics of Okinawan longevity food”. Asia Pacific J Clin Nutr.

  • Bipul Kumar

    exactly,I believe this is a very good point.but the animals I eat are raised in exactly the same way that my grandparents and their grandparents raised them.

  • Kyle Key

    So since humans eating C3 plants for millions of years isn’t up for debate, you’re admitting that humans have eaten legumes and grains for millions of years.

    • heinrich6666

      Humans or ‘human ancestors’? You’re rather mistaken if you think this research establishes that anatomically modern humans have been eating legumes and grains for ‘millions of years’ … given that anatomically modern humans have only been around for 200,000 years or so. Try again.

  • Agnes Debinski

    I am not into diets myself, but this article was very informative. It helps me relish my porridge even more.

  • Guest

    No its not

  • Martin351

    People can claim all they wan’t that whole grains are nutritious, but the fact of the matter is, there are far better options available. Take for instance a bowl of whole oats or brown rice (both whole grains)..

    is anybody going to really argue that eating either of those is better than eating a bowl nutritious veggies and fruits with a spoonful of coconut oil?

    Get real

    This isn’t really even about whole grains itself, the argument that gets tossed everywhere is grains in general. Normally this crap gets inundated with cancer causing crap and anti-nutrients in the process. I’m sorry but your “healthy” cereal, your brown or whole wheat bread, your wheat thins, and other low fat optional grains just aren’t what they are cracked up to be.

    Is it really that hard to just grab some carrots, celery up and add that to some raw spinach and eat that instead? Your body will thank you for it.

  • agnes debinski

    I feel fine when eating porridge and brown sandwich bread, but I do combine this “diet” with the consumption of meat, eggs, fruit, vegetables, sweets etc. However I wouldn´t want to have to live on spaghetti, white bread and loads of candy. My stomach was never able to handle such a life style. So I must agree with this theory to a certain extent.

  • CastaNefasta

    We are not our ancestors, they remained primates because of their diet. That’s the point, our human ancestors had a different diet, the paleo diet.

  • guruurug

    Every fad diet, which is what paleo is, has one single purpose, to make money off suckers. Why do you think there are so many religions? There’s always a willing sucker wanting to believe. The latest fad(sham) is keto.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar