Ancestral Nutrition: An Alternative Approach

I gave that title to the talk I will give at the Ancestral Health Symposium this Friday morning at UCLA.

I wrote this description of it:

For about 65 million years our primate ancestors consumed plant-dominated diets. Humans developed the technological ability to consume meat-based diets only within the last 2 million years, so at least 98 percent of the evolution producing our basic primate physiology occurred before humans could obtain meat-based diets.

Condensing the 65 million years of primate evolution into a 24 hour period, our ancestral diet was plant-based for at least 23 hours and 30 minutes, and animal-based diets emerged only within the last 30 minutes.

Ninety-eight percent of the human genome is identical to the nearest primate relative, chimpanzees, who eat a 95 percent plant diet.  Recent hunter-gatherers consume up to 20 times more meat than chimpanzees on a percent energy basis, a substantial deviation from the primate baseline.     

Similar to other primates, humans retain many physiological and behavioral features displaying adaptation to a plant-based diet, some of which are potentially maladaptive for diets supplying a high proportion of energy from meat, fat, or refined carbohydrates.  Recent hunter-gatherers and pastoralists appear protected from maladaptive responses to animal-based diets by their baseline body composition, ecological context, low total energy intake, and evolved non-nutritive ingestive behaviors. 

Modern people adopting meat-based ‘paleo-facsimile” diets may differ from recent hunter-gatherers in lifetime caloric balance, body composition, ecological context, and non-nutritive ingestive behaviors.   By comparing hunter-gatherers and modern people, I show how the quality, quantity, and context of meat consumption will affect the outcome for any individual. 

Plant and animal foods generally have opposite yet complementary nutritional characteristics.  I present an integration of Chinese medical yin-yang theory with Western nutrition that can enable us to understand the relation each type of food (plant or animal) to modern diseases of deficiency or excess,  and can help guide us to identify an appropriate dietary plant-animal ratio for any individual.

 Time permitting, I plan to post a preview sometime later this week, and after the symposium, I will present the lecture in blog form.  

Meat-Based Diet Made Us Smarter

NPR online has published online an article discussing the role of meat-eating in human brain evolution.  The author, Christopher Joyce, interviews both Leslie Aiello, co-author of the Expensive Tissue Hypothesis, and Richard Wrangham, the vegetarian primatologist who believes that cooking meat played a very important role in brain evolution.

This article has some real choice passages, like this one from Aiello:

"You can't have a large brain and big guts at the same time," explains Leslie Aiello, an anthropologist and director of the Wenner-Gren Foundation in New York City, which funds research on evolution. Digestion, she says, was the energy-hog of our primate ancestor's body. The brain was the poor stepsister who got the leftovers.

Until, that is, we discovered meat.

"What we think is that this dietary change around 2.3 million years ago was one of the major significant factors in the evolution of our own species," Aiello says.

In fact, new data suggests that this change took place at least 3.4 million years ago.

Previously unknown to me, Aiello says we have some extraordinary data that indicates that our ancestors scavenged meat from carcasses shared with wild dogs and hyenas:

"The closest relative of human tapeworms are tapeworms that affect African hyenas and wild dogs," she says.

So sometime in our evolutionary history, she explains, "we actually shared saliva with wild dogs and hyenas." That would have happened if, say, we were scavenging on the same carcass that hyenas were.

But dining with dogs was worth it. Meat is packed with lots of calories and fat. Our brain — which uses about 20 times as much energy as the equivalent amount of muscle — piped up and said, "Please, sir, I want some more."

 This "dining with dogs" may have had other consequences for human evolution.  MSN online reports that dogs, not chimps are most like humans in social behavior.  I feel inclined to turn this around to say that humans behave more like dogs than like chimps--more like pack hunters and less like solitary mostly vegetarian chimps.  The lead author of this comparative study of dog and human behavior, Jozsef Topal explained to Discovery News "that shared environment has led to the emergence of functionally shared behavioral features in dogs and humans and, in some cases, functionally analogous underlying cognitive skills."  In other words, humans who dined with dogs and behaved more like dogs and less like chimps had greater success in the hunt so that today we behave more like dogs than like chimps.

Back to the NPR article:

"As we got more [meat], our guts shrank because we didn't need a giant vegetable processor any more. Our bodies could spend more energy on other things like building a bigger brain. Sorry, vegetarians, but eating meat apparently made our ancestors smarter — smart enough to make better tools, which in turn led to other changes, says Aiello." 

Those other changes included reduction of the size of teeth and mouth as we adapted to use of "external teeth" i.e. knives.  I often remark that this adaptation made the smile possible.  After all, when an animal with hefty canines bears its teeth, it doesn't exactly warm the heart with joy.

The Raw Deal


Currently raw food diets seem popular.  The raw fooders seem fond of pointing out the no other animal cooks food, and they think this shows that cooking is "unnatural."  They also like to point out that cooking can destroy components of food.

Well, no other animal uses computers, composes symphonies, or writes sonnets.  Wrangham points out that we have good reason to believe that we wouldn't have the brain we need to do these things if we hadn't started cooking.  From the NPR article: 

Wrangham explains that even after we started eating meat, raw food just didn't pack the energy to build the big-brained, small-toothed modern human. He cites research that showed that people on a raw food diet, including meat and oil, lost a lot of weight. Many said they felt better, but also experienced chronic energy deficiency. And half the women in the experiment stopped menstruating.

It's not as if raw food isn't nutritious; it's just harder for the body to get at the nutrition.

Wrangham urges me to try some raw turnip. Not too bad, but hardly enough to get the juices flowing. "They've got a tremendous amount of caloric energy in them," he says. "The problem is that it's in the form of starch, which unless you cook it, does not give you very much."

Then there's all the chewing that raw food requires. Chimps, for example, sometimes chew for six hours a day. That actually consumes a lot of energy.

"Plato said if we were regular animals, you know, we wouldn't have time to write poetry," Wrangham jokes. "You know, he was right."

Wrangham eats a vegetarian diet, but notes that the art of cooking meat gave our ancestors important advantages: 

Besides better taste, cooked food had other benefits — cooking killed some pathogens on food.

But cooking also altered the meat itself. It breaks up the long protein chains, and that makes them easier for stomach enzymes to digest. "The second thing is very clear," Wrangham adds, "and that is the muscle, which is made of protein, is wrapped up like a sausage in a skin, and the skin is collagen, connective tissue. And that collagen is very hard to digest. But if you heat it, it turns to jelly."

As for starchy foods like turnips, cooking gelatinizes the tough starch granules and makes them easier to digest too. Even just softening food — which cooking does — makes it more digestible. In the end, you get more energy out of the food.

That increased energy goes to our head!  Our brains use about 25% of our resting energy expenditure, compared to 8-9% for a chimpanzee. So if you want to think like a chimp, go for the raw food diet; but if you want to be human, use fire:

Yes, cooking can damage some good things in raw food, like vitamins. But Wrangham argues that what's gained by cooking far outweighs the losses.

As I cut into my steak (Wrangham is a vegetarian; he settles for the mango and potatoes), Wrangham explains that cooking also led to some of the finer elements of human behavior: it encourages people to share labor; it brings families and communities together at the end of the day and encourages conversation and story-telling — all very human activities.

"Ultimately, of course, what makes us intellectually human is our brain," he says. "And I think that comes from having the highest quality of food in the animal kingdom, and that's because we cook."

New data: Human ancestors eating meat 3.4 million years ago

New Scientist has published an article online reporting on new archaeological finds that indicate that Early humans were butchers 3.4 million years ago.  The article reports:

"Our ancestors were carving meat some 800,000 years earlier than previously thought. Marks on fossilised animal bones found in Ethiopia indicate that early-human butchers were using stone tools as early as 3.4 million years ago.

Shannon McPherron of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues say the find is evidence that Australopithecus afarensis – the only known hominin species present in the region at the time – used tools.

The finds suggest that the evolution of toolmaking and meat-eating among our human ancestors is more complex than existing theories admit.

They also add to a growing body of evidence that A. afarensis may have been more human-like and less primitive than some have assumed."

The new data indicates that A. afarensis used tools to butcher a large mammal similar in size to a modern cow.  This means that he very deliberately (not accidentally) ate the red meat so dreaded by modern people.   Apparently he understood the advantages of red meat over poultry...and of the fat found in marrow:

"What we have done is push back in time, rather dramatically, two of the more fundamental behaviours that played such an important role in our evolution – meat consumption and tool use," says McPherron. "This find forces us to rethink the idea that the origins of stone tool use, meat consumption and the origins of our genus Homo all occurred together, around 2.5 million years ago."

Instead, he says, it's likely that hominins at least experimented with stone tools to help them eat meat and marrow much earlier.

The article carries the following two images of the bones with cut marks from stone tools used to butcher the animal:

So now it appears that the ancestral group to which Lucy belonged relished red meat and had tools for the purpose nearly a million years before H. habilis showed up.  If so, this means that we have eaten red meat for at least 340 times as long as any human group has eaten grain-based diets found in agriculture.

Loren Cordain Responds To Mercader Paper on Grains in Stone Age Diets

Today I received an email from Loren Cordain in which he comments on the articles entitled "Mozambican Grass Seed Consumption During the Middle Stone Age" by Julio Mercader in the journal Science, and "Humans feasting on grains for at least 100,000 years," (feasted? can you say hyperbole?) by Katherine Harmon in Scientific American, which stirred up some in the paleo community, and on which I a couple of days ago in Did Stone Age People Eat Grains (Much)?

I reproduce Dr. Cordain's comments in full:

This is an interesting paper ( Mercader J. Mozambican grass seed consumption during the middle stone age. Science 2009;326:1680-83) as it may push probable (but clearly not definite) cereal grain consumption by hominins back to at least 105,000 years ago. Prior to this evidence, the earliest exploitation of wild cereal grains was reported by Piperno and colleagues at Ohalo II in Israel and dating to ~23,500 years ago (Nature 2004;430:670-73). As opposed to the Ohalo II data in which a large saddle stone was discovered with obvious repetitive grinding marks and embedded starch granules attributed to a variety of grains and seeds that were concurrently present with the artifact, the data from Ngalue is less convincing for the use of cereal grains as seasonal food. No associated intact grass seeds have been discovered in the cave at Ngalue, nor were anvil stones with repetitive grinding marks found. Hence, at best, the data suggests sporadic use (and not necessarily consumption) of grains at this early date. Clearly, large scale processing of sorghum for consumption for extended periods seems unlikely.

Further, It should be pointed out that consumption of wild grass seeds of any kind requires extensive technology and processing to yield a digestible and edible food that likely did not exist 105,000 years ago. Harvesting of wild grass seeds without some kind of technology (e.g. sickles and scythes [not present at this time]) is tedious and difficult at best. Additionally, containers of some sort (baskets [not present at this time], pottery [not present] or animal skin containers are needed to collect the tiny grains. Many grain species require flailing to separate the seed from the chaff and then further winnowing ([baskets not present]), or animal skins] to separate the seeds from the chaff. Intact grains are not digestible by humans unless they are first ground into a flour (which breaks down the cell walls), and then cooked (typically in water – e.g. boiling [technology not present]) or parched in a fire which gelatinizes the starch granules, and thereby makes them available for digestion and absorption. Because each and every one of these processing steps requires additional energy on the part of the gatherer, most contemporary hunter gatherers did not exploit grains except as starvation foods because they yielded such little energy relative to the energy obtained [sic -- I think he meant expended - DM](optimal foraging theory).

If indeed the grinder/core axes with telltale starch granules were used to make flour from sorghum seeds, then the flour still had to be cooked to gelatinize the starch granules to make it digestible. In Neolithic peoples, grass seed flour most typically is mixed with water to make a paste (dough) that is then cooked into flat breads. It is highly unlikely that the technology or the behavioral sophistication existed 105,000 years ago to make flat breads. Whole grains can be parched intact in fires, but this process is less effective than making flour into a paste and cooking it to gelatinize the starch granules. Hence, it is difficult to reconcile the chain of events proposed by the authors (appearance of sorghum starch granules on cobbles or grinders = pounding or grinding of sorghum grains = consumption of sorghum). I wouldn’t hang my hat on this evidence indicating grains were necessarily consumed by hominins at this early date. To my mind, the Ohalo II data still represents the best earliest evidence for grain consumption by hominins.

Cordially,
Loren Cordain, Ph.D., Professor

I haven't read the articles myself yet, only the press release with quotes from Mercader, but it looks like Cordain has and, as I imagined, the Mercader paper apparently lacks critical evidence for establishing consumption of grains, let alone "feasting" as Katherine Harmon states in the title of her Scientific American article. To me this looks like a classic example of an author getting a paper published just because it fits with the views of a "knowledge monopoly/research cartel" such as discussed by Henry H Bauer (Professor Emeritus of Chemistry & Science Studies, Dean Emeritus of Arts & Sciences, Virginia Polytechnic Institute & State University) in his article "Science in the 21st Century: Knowledge Monopolies and Research Cartels" (J Scientific Exploration, Vol. 18, No. 4, pp.643-660, 2004).

That is, the established knowledge monopoly/research cartel serves to support government-endorsed views of nutrition (i.e. food pyramid), so they grasp at any straw to lend support to their conception of good, grain-based nutrition.

New Hominid Findings

Ardipithecus image source: BBC

Science has a set of new articles from a team of researchers that have studied one of the now oldest known hominids, Ardipithecus ramidus, dated to about 4.4 million years ago.

The skeletal remains indicate that "Ardi" walked upright but still had prehensile feet with opposable large toes enabling it to climb and nest in trees. Unlike later, grassland-dwelling hominins, Ardi "lived in a woodland, climbing among hackberry, fig, and palm trees and coexisting with monkeys, kudu antelopes, and peafowl" according to Ann Gibbons, author of the article Habitat For Humanity, available free online after registration.

This find indicates that key human features appeared in the hominids inhabiting woodlands. Consequently, we can no longer explain some of those features--such as bipedalism--as adaptations to a grassland habitat.

Regarding Ardi's diet, according to Gibbons,

"The team suggests that Ar. ramidus was 'more omnivorous' than chimpanzees, based on the size, shape, and enamel distribution of its teeth. It probably supplemented woodland plants such as fruits, nuts, and tubers with the occasional insects, small mammals, or bird eggs. Carbon-isotope studies of teeth from five individuals show that Ar. ramidus ate mostly woodland, rather than grassland, plants. Although Ar. ramidus probably ate figs and other fruit when ripe, it didn't consume as much fruit as chimpanzees do today."

To clarify, by "more omnivorous" they mean that Ardi ate more animal food so it would be more appropriate to say that Ardi ate more carnivorously than chimpanzees. Ardi's diet of animal foods, fruits, nuts, and tubers sounds a lot like many recent hunter-gatherer diets.

Ardi also lacks the large, honing canines present in chimpanzees, which according to C. O. Lovejoy (Reexamining Human Origins in Light of Ardipithecus ramidus) indicates that Ardi tribes most likely had reduced male-to-male conflict compared to apes. Based on this, Lovejoy also believes that Ardi probably "...combined three previously unseen behaviors associated with their ability to exploit both trees and the land surface: (i) regular food-carrying, (ii) pair-bonding, and (iii) reproductive crypsis (in which females did not advertise ovulation, unlike the case in chimpanzees)" and that that "Together, these behaviors would have substantially intensified male parental investment—a breakthrough adaptation with anatomical, behavioral, and physiological consequences for early hominids and for all of their descendants, including ourselves."

In Paleobiological Implications of the Ardipithecus ramidus Dentition Gen Suwa et al conclude that the Ardi data suggests that "fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools."

I have not read all the articles yet, but as I contemplated this woodland origin of hominids, I thought of the aurochs, the ancestor of modern cattle. Although we raise cattle on open grasslands today, the Extinction Website states that the aurochs "appears to have preferred swamps and swamp woods, like river valleys, river deltas, and different kind of bogs. Beside swamp woods the aurochs shall also have lived in less wet forests." I have understood that this provides one reason cattle so easily damage open ranges compared to bison, i.e. cattle are naturally adapted to woodlands, and are more natural browsers than grazers.

Aurochs and wolves image source: The Extinction Website

The aurochs' range included North Africa, and I don't know if it ever ranged in the area where archaeologists unearthed Ardi (Ethiopia). Nevertheless, my mind went to consider the possibility that the hominid relationships with cattle and wolves (dogs) began in woodlands, not grasslands. Ardi is a fascinating find.