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Podcast: Lions Do Not Eat Grass

By The Paleo Diet Team
February 27, 2014
Podcast: Lions Do Not Eat Grass image

Dr. Loren Cordain: I'm Loren Cordain, Founder of the Paleo Diet Movement.

Shelley Schlender: I'm Shelley Schlender. This is The Paleo Diet Podcast for December 2014.

Dr. Loren Cordain: Just because you see a C4 signature does not mean they're eating grass or sedges.

Shelley Schlender: Should we start with that? You think?

Dr. Loren Cordain: Sure.

Shelley Schlender: Loren Cordain, there's a lot more that archaeologists and anthropologists and Paleo researchers can analyze from ancient people to see what they really ate in ancient hominids.

Dr. Loren Cordain: That's right. There is a number of isotopic signatures that can be found in preserved tissues of our ancestors that give us somewhat of an indication of what they've been eating. If you go back 2 or 3 million years, there is some argument in the anthropology community of whether or not you're actually getting intact isotopic carbon.

Shelley Schlender: Where do they scrape this off of? When you have a 2 or 3 million-year-old bone of a hominid, where do you get the isotopic signature of what they ate?

Dr. Loren Cordain: Bones really don't preserve it very well because there's a process called diagenesis. In the bones, they don't preserve the isotopes that we're interested in, which is Delta Carbon 13, which is a reflection of the types of plant foods, the enamel or an organism has been consuming. What we have to rely on is enamel.

Shelley Schlender: Tooth enamel.

Dr. Loren Cordain: Yeah, because tooth enamel is a really hard substance. This diagenesis, this process that breaks down carbon, is less likely to occur.

Shelley Schlender: A shiny smile, which depends on tooth enamel, is not only good for appearance but 2 million years from now, if there are researchers, they would be able to understand more what we ate.


Dr. Loren Cordain: Colleagues of mine and people that do these analyses, that's what they're looking for, is that they do the Delta 13 Carbon analysis from teeth, primarily, because the bones, the carbon signature seems to have broken down.

Shelley Schlender: It's quite amazing to think that our shiny tooth enamel holds the signature of what we've been eating.

Dr. Loren Cordain: That's true. If you were to look at modern humans, we don't have to worry about the carbon signature breaking down. We can take any tissue we want. We can take hair and we can take cells from the inside of our mouth, or we could take tooth enamel if we would like. What we find is that the signature in modern humans shows us to be essentially grass eaters. There's two types of photosynthetic plants, there’s C3 and C4 plants. The C4 plants are grasses and sedges and the C3s are shrubs and fruits and what have you.

Shelley Schlender: Loren Cordain, it's been a long time since I ate grass.

Dr. Loren Cordain: Actually not. If you're a normal American, you consume grass, probably everyday of your life.

Shelley Schlender: But I don't eat grass. What are talking about here?

Dr. Loren Cordain: I'm talking about a grass that you do eat everyday of your life, it's called corn. Corn is a grass.

Shelley Schlender: Oh so it can be the seeds and if you eat corn oil, which means if you go any restaurant and you're having corn oil, or you can have tortilla chips.

Dr. Loren Cordain: How about high fructose corn syrup?

Shelley Schlender: Oh that.

Dr. Loren Cordain: They put that in everything. If you have hi-fructose corn syrup, which most Americans eat every single day through their soda pop, then that creates this C4 signature.

Shelley Schlender: That's the signature of a grass eater, but in this case, it's the sugar that was made from the grass.

Dr. Loren Cordain: That's right. We can even go one step further, is that, when was the last time you had a hamburger?

Shelley Schlender: Well, probably last week.

Dr. Loren Cordain: Okay, or how about beef?

Shelley Schlender: Yes, I had a hamburger without the bun but that still counts. Doesn't it?

Dr. Loren Cordain: Okay how about chicken? When was the last time you had beef, chicken, or pork?


Shelley Schlender: I have eaten those.

Dr. Loren Cordain: Most Americans eat those on a very regular basis. What we feed our pigs and our cows and our chicken? What is the primary food that we feed them in a feed lot?

Shelley Schlender: Well, let's see. Is it corn?

Dr. Loren Cordain: It's corn, exactly. That signature for their meat, we eat their meat. We now have the signature from hi-fructose corn syrup from meat, from chips and all the other products that we make out of corn.

Shelley Schlender: It's not a pleasant feeling to look down at a body of yourself and look and think, "Gosh I'm just a whole bunch of corn."

Dr. Loren Cordain: If we were to do the analysis of modern humans and we didn't know what we were eating, and we see this huge C4 signature, then some anthropologists would suggest that we are grass eaters when in reality we're not eating grass per se. We're eating products of grass that come down through our food chain. That's the real problem with the interpretation.

Shelley Schlender: Just hold on a second. You're concerned that the anthropologists who are looking at teeth enamel from 2 million years ago, are saying that it implies that our ancestors were grass eaters. But today we eat grass it's because we can process them in so many ways. We can put them in corn syrup. We can put them in a lot products that hominids, didn't have available 2 million years ago.

Dr. Loren Cordain: That's right. But the process remains the same. It's whether you eat it directly or whether you get it indirectly from an animal that is eating those C4s, the grasses or the sedges, you can't interpret it. My colleagues that I've worked with internationally, we have criticized Dr. Sponheimer at CU for interpreting the data from the fossils that they have found in tooth enamel from hominids. They looked at these over a 4 million year period.


What they increasingly see, starting in, when hominids began to make stone tools, they increasingly see the C4 signature. Their interpretation was our ancestors were eating more and more grasses or sedges.

Shelley Schlender: Before we go to the punchline on that, what I've heard you say is that you have great admiration for Dr. Sponheimer's research in terms of the data gathering. It's an incredible way to be gathering and figuring out how to find these clues from 2 or 3 million years ago. He has done a masterful job of that, you just have concerns about what the conclusions from that are.

Dr. Loren Cordain: That's right, I have enormous respect for Matt. He and I, our histories go back for years and years and years. We've spoken at conferences. I consider him a good colleague. But the interpretation of the data that he has presented recently, needs to be guarded. It needs to be interpreted more conservatively. Just because you see a C4 signature in these teeth of hominids, does not indicate they're eating more grasses or sedges. In reality, it seems likely that they were eating the flesh of animals that were eating grasses and sedges.

Shelley Schlender: We don't know that for sure. If you're a vegan for instance, somebody who doesn't want to be eating animal products, you could use Matt's research to imply that our hominid ancestors were vegans and they just ate grasses.

Dr. Loren Cordain: Shelley, I disagree with that interpretation, very heartily.

Shelley Schlender: But the vegans don't.

Dr. Loren Cordain: I don't care, because if you take raw grass seeds - I don't care whether it's wheat or corn or rye or barley or any cereal grain - and you put it in your mouth and you chew it up, it is virtually and totally indigestible by the physiology of hominids.


We simple do not have the enzymes and the ability or gut bacteria to break down the starches that are found and the proteins that are found in cereal grains. Grains, if you put them in your mouth, they come right out your GI tract and your feces like you put them in. They are almost entirely, indigestible.

Shelley Schlender: Loren Cordain, that’s true for modern humans but this was 2 - 3 million years ago. Could it be that our hominid ancestors had a better gut for digesting these grains?

Dr. Loren Cordain: No that's ridiculous. We know what the GI tract of primates look like. We know what the gastrointestinal tract of gorillas and our closest living ancestor chimpanzees and monkeys and virtually all primates. There's only a single primate that has the ability to utilize the starches in grains and that's a baboon called a Gelada baboon. It has a very large hindgut. Because of the large hindgut, then it has bacteria that can ferment the starches that are found in grains. By being able to do it, it ferments it and it produces what are called short chain fatty acids. It can take those short chain fatty acids then and utilize them as energy.

No other primates can do that. No other primates eat grains. The interpretation of a C4 signature in our ancestors that live for to 3 to 2 and 1 million years ago, simply is not reflective of eating grasses or sedges, it's reflective of eating animals that ate grasses or sedges. This corresponds with the appearance of stone tools in the fossil record. What were they doing with those stone tools? You think they were harvesting grains? No. Absolutely not. We know that the stone tools were used to butcher and disarticulate animals that were living in these grasslands, Serengeti and so forth, it expanded during this period.


We know that there is an enormous expansion of grasslands in East Africa, where the fossils are found, starting in about 3 million years ago. What most anthropologist believe is then we had to move in to these grasslands as the forest tended to decline over that 2-3 million year period and then the food that we were consuming was animal food. The C4 signature, then, represents the consumption of more and more animal foods.

Shelley Schlender: OK let's see if I can track this through and, what was it again? C4, C3 that means grass.

Dr. Loren Cordain: Grass is C4. There's a different photosynthetic pathway that grasses take. The types of carbon - it's called Delta 13 Carbon - that we find in grass eaters, which are grazers versus browsers, who eat fruits and vegetables and other plant foods, is distinctly different. The Delta Carbon 13 signature is completely different and that's, really, what's analyzed.

Shelley Schlender: C4 for grass.

Dr. Loren Cordain: Grass and sedges.

Shelley Schlender: Sedges. Matt Sponheimer's research shows that, before this time, the tooth enamel shows a lot of C3, which means that there was more eating of leaves, fruit and they really could have been much more vegetarian at the point.

Dr. Loren Cordain: That's absolutely the case. We know that now from the geologic record. By drilling cores off the coast of East Africa into the mud of the ocean, we can see what was going on climatically. Prior to this time, before 3 million years ago, East Africa was a lot wetter and it allowed for more of a tropical forest. The primates, then, were living primarily in a tropical forest, in which there were a lot of C3 plants.


Shelley Schlender: They were more Vegan-oriented except for the insects that they ate and the snakes that they ate and the other smaller primates that they ate and anything else like that, but it wouldn't show up as the fact that they had eaten any animal products because all of their food came from other animals eating C3, fruits and leaves.

Dr. Loren Cordain: Actually interpretation is, because there was this enormous tropical rainforest that they were living in and exploiting, it seems likely, when we look at other primates that live in tropical rainforest, is that the majority of their calories come from C3 plants themselves. If you look at a chimp, they eat a lot of fruit, 80% of their calories come from fruits. If you look at gorillas who live in the same environment, many of their calories come from leaves and bark and more roughage than chimps do. But primarily, when primates’ liver, regardless of which species of primates, when they live in tropical rainforest, their diet is, I won't say entirely, but very highly composed of these C3 plants. They eat a lot of fruit.

What happened, we know from Peter deMenocal’s work is that there were changes in the climate that went back and forth and back and forth, from dry to wet to dry to wet. But the overall picture, starting in about 3 million years ago, is that what we call Savannah environment started to prevail. A lot of the forest then turned into permanent Savannah. We know this from recent drillings by deMenocal and other scientists.

What happened then, is the tropical rainforest and the primates that were eating C3 plants now had to move out onto the Savannah, this grassland. The interpretation could be one of two things, "Oh now they're starting to eat more and more grass", or two, "They're eating animals that ate grass."


The second interpretation is what our group believes. This is our criticism of Matt Sponheimer's work, that because physiologically, primates don't have the ability to digest grasses then the signature, in all likelihood, represents them eating more animal foods of animals that were eating C4 or grasses.

Shelley Schlender: Loren Cordain, if you took the tooth enamel of an African Lion that was out in the Savannah, what would it show?

Dr. Loren Cordain: It shows a mixture. It falls in between C3 and C4, because a lion or a leopard or even a hyena, clearly don't eat grass. They're obligate carnivores. They eat a variety of animals. They eat animals that are browsers, so those who'd be C3 type signatures, and they also eat animals that are grazers. That's why they have a mixed signature.

That's exactly what we see from these hominids in East Africa, is that even though Sponheimer's work suggest that they move from more of a C3 to a C4 signature, they still follow someone in between. The interpretation then ... I believe the correct interpretation is that that intermediary is because they were eating more and more animal foods. The animal foods that they consumed, they didn't care if the animal was a browser or a grazer. If they had the flesh, that animal, they would eat it.

That's all for this edition of the Paleo Diet Podcast.

Shelley Schlender: Our theme music is by chapman stick soloist, Bob Culbertson.

Dr. Loren Cordain: Visit my website, for past episodes and for hotlinks to my research studies, books and latest writings. For questions or comments, the place to go is the


Shelley Schlender: For the Paleo Diet Podcast, I'm Shelley Schlender.

Dr. Loren Cordain: I'm Loren Cordain.

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