I wanted to get into the diet portion of the book, but first, I want to deal directly with the Paleo Diet. Pontzer paints all proponents of the Paleo diet with a sweeping—and quite unflattering—brush as examples of the Dunning-Kreuger effect in action (p. 193), and their prohibitions on certain foods as akin to a religious practice based on irrational food taboos (p. 208)—a common dismissal tactic used against any diet that prohibits certain types of foods.
One thing that bothers me about these alleged “debunkings” is that they usually argue against a straw man. The strenuously argue against claims that no one associated with the Paleo Diet ever actually makes, save for a few extreme or fringe voices. These criticisms are always targeted at the most extreme adherents, rather than those who are the most mainstream and have done the most serious work. Many of the authors behind the original Paleo Diet concepts are doctors, physiologists, anthropologists, and other people with advanced degrees. Many of their writings are based on peer-reviewed papers published in academic journals. But too often those people are ignored in favor of the people making the most extreme and outrageous claims, regardless of their actual qualifications (or lack thereof).
Which beings up a related problem—literally anyone can write a book or publish a blog post on the internet making assertions about ancestral health without any kind of oversight. There are certainly claims made by some Paleo Diet advocates that do not hold up to scrutiny, to be sure, but is that a reason to dismiss everything about it?
Which brings up the second point. A lot of people assume the Paleo diet is based on some kind of historical reenactment of what people were eating during the Stone Age. It's quite clear that the people who are making this argument have never actually read a book about the Paleo Diet. The fact that our food has been profoundly transformed by selective breeding and that we rely on domesticated food resources is true, of course, but all serious Paleo authors are aware of that fact. The idea is trying to eat foods that are the closest approximation to what our ancestors ate, rather than trying to mimic the extinct lifestyles of people hundreds of thousands of years ago.
Third, a lot of the criticism is simply based around ridicule. These people assume—without evidence—that the Paleo Diet is sort of a “cosplay” of what life was like during the Stone Age. Such people pejoratively refer to it as the "caveman" diet, depicting its adherents as dim-witted, knuckle-dragging brutes. Perhaps the most egregious example was Bill Nye's dressing up a person in a silly caveman outfit for his alleged "debunking" of the Paleo diet.
Finally, many of these criticisms conflate several different diets—Paleo, Atkins, and Ketogenic. The Atkins diet is expressly a low-carb, high fat diet, advocating (often non-Paleo) foods like bacon and butter, while the Ketogenic Diet is a very low-carb diet intentionally designed to put people into ketosis which was originally developed to treat severe epilepsy. The Paleo diet is distinct from either of those, and does not eschew either carbohydrates or plant foods. Neither is it an "all meat" diet as is often portrayed, which is actually the so-called "carnivore" diet. Here’s Pontzer's working definition of the diet, which reads like a parody based on a sampling of random internet blog posts:
In the hot, crowded ecosystem of competing dietary movements, the loudest voices seem to attract the most attention. Paleo diet evangelists have distinguished themselves by projecting a hard-nosed, steel-eyed view of human nature and evolution. Humans, they assure us, have evolved to eat meat, bro. They push high-fat, low-carb diets that send the body into ketogenesis, arguing that our ancestral diet was all bison and no berries.
Paleo proponents, particularly the self-styled carnivores, reject the notion that vegetarian or (god forbid) vegan diets are healthy or natural, dismissing plant-based recommendations or cautions about fat as politically correct pandering or corporate propaganda. In their view, no self-respecting hunter-gatherer would eat a starchy, carb-rich diet, and they sure as hell wouldn't eat any sugar. (B: 194)
I'm sorry, but that is just ridiculous. It's about as responsible as Bill Nye's hi-jinks. He should know better. He could have simply, well, read the actual literature from legitimate Paleo Diet sources—some of which are academic papers—to find out whether this characterization was accurate or not. For example:
Many people mistakenly believe that by following The Paleo Diet you must consume copious amounts of animal protein. However, that simply is not the case. While The Paleo Diet allows for meat and eggs, it also encourages a good variety of whole, plant-based foods...Depending on the definition used, and by removing dairy from the list, a “plant-based” diet could include The Paleo Diet...Fortunately, you can still eat a plant-based diet and stay Paleo...
What Does “Plant-Based” Really Mean? (The Paleo Diet)
There is an unfortunate misconception about The Paleo Diet® that it is a primarily meat-based diet. Images abound of a brutish caveman (a term we don’t like here at The Paleo Diet) clubbing his food to death and eating it raw in a dark cave.
Unfortunately, that perception of the diet was furthered by a misinterpretation of one of Dr. Loren Cordain’s first studies where he noted that most hunter-gatherer societies that have been studied consumed over 50 percent of their food from animal sources versus plant sources. It’s a misinterpretation because he was describing their diets by calorie, not by volume—and there’s a very big difference.
Is The Paleo Diet Meat or Plant-Based? (The Paleo Diet)
So the big question – is a ketogenic diet Paleo? Our ancestors were not perpetually in ketosis, but clearly they were keto-adapted, meaning they could efficiently enter ketosis, depending on their circumstances.
There is considerable overlap between the contemporary Paleo diet and the ketogenic diet and because ketosis has both an evolutionary precedent and verifiable health benefits, it seems appropriate to incorporate ketosis into the Paleo template. This could occur in numerous ways, including through occasional fasting, intermittent fasting, and by periodically cutting one’s carb intake to less than 50 g/d, perhaps for several days, weeks, or months at a time.
The Ketogenic diet, is it paleo? (The Paleo Diet)
I’m all for criticism, but criticism of what your opponents are actually saying. The basic idea is simply that our bodies were designed by natural selection to eat certain types of foods. The same is true for literally any animal. It's hard to argue against this.
I think it boils down to fact that "serious" scientists don't lend credence to what are perceived to be popular fads, especially scientists from prestigious universities like Dr. Pontzer. They would risk their reputations. So instead of looking for aspects of the diet that might have merit, they feel the need to ridicule and "debunk" it to maintain their status as "serious" scientists. That leads them to making spurious arguments and straw man attacks. 1 Let's try and be a little more charitable shall we?
The Origins of the Paleo Diet
The fact that native and indigenous communities all over the world were largely free from the diseases of civilization had attracted the attention of people for a long time. During the Victorian era, however, the predominant narrative was one of civilizational progress where everything about modern life was an improvement over the lives of so-called "primitive" peoples, including health and nutrition.
It was assumed for a long time that people not engaged in farming or herding were living precarious lives on the edge of starvation and that farming had been a brilliant innovation to overcome this difficulty—an innovation that certain native peoples stubbornly refused to adopt because of their supposed "backwardness." Tribal and band societies were portrayed as somehow stunted and defective, like seeds that had fallen on poor soil and failed to sprout.
The fields of anthropology and archaeology would eventually come to refute these ideas. At the pivotal 1966 symposium Man the Hunter, anthropologists like Richard Lee and Irven DeVore revealed that hunter-gatherers did not, in fact, live on the edge of starvation as was presumed in the Victorian era. Rather, their diets—based upon wild foods harvested directly from nature—were more dependable and nutritious than those of nearby farmers who got most of their nutrition from a single crop and were perennially threatened with famine and starvation. At the same time, the emerging field of bioarchaeology was revealing that the transition to farming took a terrible toll on human health. Jared Diamond summarized the evidence in a highly influential 1987 Discover Magazine article entitled The Worst Mistake in The History of the Human Race?
This information was the inspiration for a diagnostic radiologist named Stanley Boyd Eaton, who teamed up with a pair of anthropologists in 1988 to write The Paleolithic Prescription. They proposed a "discordance hypothesis" which argued that the fundamental cause of growing maladies like obesity, diabetes, and heart disease was a mismatch between the modern world and the environments that humans had evolved in. This was probably the first popular book expounding what would later be known as "ancestral health."
The advocates of ancestral health pointed out that between hunter-gatherer times and now there have been some 500 generations, whereas during hunter-gatherer times there were over 100,000. Our modern world of automobiles, electric lights and television was even more recent, being less than a handful of generations old. Our bodies and minds evolved and adapted to a hunter-gatherer existence, and not to the conditions prevalent in modern industrial societies. This, they said, was the fundamental root cause behind all sorts of maladies, both physical and psychological.
Their work attracted the attention of an exercise physiologist named Loren Cordain, who published a number of academic papers on the discordance hypothesis and the diets of hunter-gatherers over several years. In 2002 he released The Paleo Diet, trademarking the term. The diet found a receptive audience, thanks in large part to the new and burgeoning internet, and many others became vocal advocates of an ancestral approach to diet and exercise. There’s more information at this link:
A Brief History of the Contemporary Paleo Diet Movement (The Paleo Diet)
The transition from a hunting-and-gathering existence to one centered around raising domesticated crops and livestock is known in archaeology as the Neolithic Revolution. Because hunter-gatherers lived outside the boundaries of civilization and did not raise crops or tend livestock, it was assumed that their diets and lifestyles were an accurate reflection of people living before the Neolithic Revolution during the Paleolithic era—that is, before the transition to agriculture. Hence the term "Paleolithic" was adopted in reference to the diet.
This turned out to be a major mistake, one that has left their conclusions open to “debunking” ever since, especially from "respectable" scientists seeking to dismiss it as just another fad diet promoted by internet charlatans.
The fact is, modern-day hunter-gatherers do not live in the Paleolithic—they live in the Neolithic just like the rest of us. Hunter gatherers have their own histories—they are not living fossils like flies preserved in amber or cavemen frozen in blocks of ice. While they may have very different lifestyles, they are every bit as "modern" as we are, even if they don't grow crops or raise animals. While anthropologists do sometimes use hunter-gatherers like the Hadza to study what human behavior and social organization might have been like during the Paleolithic, they are very careful to point out the pitfalls and limitations of doing so.
What We Talk About When We Talk About Paleo
The transition to farming was accompanied by a new climatic regime—the Holocene—which affected everyone on the planet, hunter-gatherers included. This means that modern hunter-gatherers are not really an accurate reflection of the human diet and lifestyle during the Paleolithic, despite the fact that they still rely mostly on wild plant and animal resources.
What the originators of the Paleo Diet really meant was "not farming." However, their unfortunate choice of terminology has given the "debunkers" plenty of ammunition ever since, and Pontzer is no exception. What such people typically do is range freely and broadly between the data on modern-day hunter-gatherers and archaeological evidence from hundreds of thousands of years ago, constantly redefining what the diet is actually trying to convey. Because of this uncertainty, there is always plenty of ammunition to "debunk" Paleo diet and its related health concepts unless we nail down exactly what we are talking about. Are we looking at hunter-gatherers today or people living during the last Ice Age?
Low Carb and High Fat?
The Paleo Diet originally billed itself as a low-carbohydrate, high-fat diet. This has been a major target of criticism by experts, especially the perceived importance of meat. For example, Pontzer laments, "Why do so may of today's Paleo evangelists insist that the 'natural' hunter-gatherer diet is low carb and high fat?" (B: 201) He adds, "Humans can be healthy eating a broad range of diets, and have done so in the past. There is no single Paleo diet." (B: 202) But is it actually the case that "Paleo evangelists,” in his words, “insist" that there really is such a thing?
What critics of the Paleo diet always point out is that the diets of indigenous peoples all over the world are incredibly diverse, with no consistent ratio of fat, protein or carbohydrates. Sometimes that meant a diet consisting of mostly plant foods, while sometimes that meant a meat-heavy diet, and pretty much everything in between. People around the world ate whatever was available in their local environment, and did not worry about any sort of macronutrient ratio.
People living closer to the polar regions generally ate diets higher in meat and fat because plant foods were less available. In tropical regions like the Amazon rain forest, on the other hand, it was the exact opposite, with most of the calories coming from plant foods supplemented by fishing. The sheer diversity of diets of native peoples around the world means that you can always find someone, somewhere with just about any nutrition content and dietary habits you care to find if you look hard enough. As Pontzer correctly states, "The range of 'natural' human diets is vast. People eat whatever is available." (B: 198)
Cordain, Eaton, and others who wanted to study the dietary habits of native peoples rarely had detailed information at their fingertips. Instead, they relied on a well-known volume called The World Ethnographic Atlas compiled by the anthropologist George Murdock in 1967, which compared 1167 preindustrial societies. This was the only source from which to draw cross-cultural comparisons, then as now. As Ponzter admits, "Like the sad hand dryer in a gas station restroom, it's far from ideal, but for most of these populations, it's all we've got." (B: 198)
The Ethnographic Atlas compared diets around the world by describing the proportion of meats, plants and fish in the diet, as well as the portion coming from domesticated crops and livestock. However, the data was based on ethnographies rather than precise data collected by anthropologists looking specifically at dietary intake and keeping detailed records. This meant that the information used by Boyd Eaton, Cordain and others was often less than accurate:
...the data from Murdock is simply not good enough to get a precise read on dietary intake. His cultural summaries don't say anything about fat, carbs, or protein. Instead, Murdock assigned a dietary score, 0 through 9, to relay a rough estimate of the contribution of different food types to the diet. For the most part, the methods used to determine those scores aren't described.
It's likely, though, that they missed a lot of carboydrate-rich foods...anthropologists in the early and mid-1900s consistently overlooked women's contributions, which would tend to underestimate the amount of plant foods. And we know that Murdock's summaries ignored honey, which is a big part of the diet for the Hadza and many other hunter-gatherers...
To come up with his dietary recommendations, Cordain took the averages of plant, fish and animal products from the diets of various peoples around the world from the Atlas. This approach is derided by Pontzer:
Another problem with Cordain's analyses is the focus on the average proportions of animals and plants rather than on the enormous diversity of diets across the globe. Focusing on the average suggests that there's one "true" natural human diet, and anything else leads to disease. That makes about as much sense as arguing that there's one "true" human height, and anyone who deviates from it is pathological. For some measures, the average value isn't very meaningful. (201-202)
But is Cordain really saying that, or is Pontzer putting words in his mouth? And are the exact proportions coming from different foods really all that important? To be fair, if you're writing a diet book, you would probably have to give out some sort of recommendations—that's standard for the genre, after all. To this end, you would be forced to oversimplify. The only way to avoid this would be to say; "Well, people can eat pretty much anything, so I can't give you any recommendations—sorry." Anything short of that leaves you open to attacks from "debunkers." But that doesn't sell diet books.
It's certainly true that there is no one Platonic ideal of a hunter-gatherer diet. Nor is there a precise macronutrient ratio that humans must eat in order to stay healthy. But I don't think Cordain and other advocates of the Paleo Diet would really insist that there is. It's worth keeping in mind the historical context in which the original Paleo Diet books and papers were published.
At that time the prevailing wisdom in health circles was that that fat—especially animal fat—was harmful and would clog your arteries and give you heart attacks. Fat was also seen as the chief culprit in rising obesity rates. The recommendation from experts was to eat foods low in fat and center your diet around multiple servings a day of "healthy whole grains." The FDA had released their infamous "food pyramid" recommending that the basis of healthy diet should be breads, cereals and pastas, supplemented by an intermediate amount of fruits and vegetables, with meat, dairy and eggs all comprising a relatively minor portion of caloric intake. This was considered to be protective from obesity and heart disease according to doctors and medical experts.
Cordain and others studying hunter-gatherer diets were bucking this conventional wisdom. To that end, they emphasized the near-total absence of grains in hunter-gatherer diets—perhaps overemphasized it. Because breads, pastas and cereals were the main source of carbohydrates in the standard American diet, this is the reason the diet focused on minimizing carbohydrate intake, even though this was not universal for hunter-gatherers. And the prevailing wisdom at the time was that consuming animal products—especially red meat—was unhealthy and that fat was the principle culprit behind rising rates of obesity and heart disease. Thus the emphasis on meat in the diets of hunter-gatherers who were free from both of those maladies. Again, perhaps they overemphasized those aspects. But they were ultimately questioning whether grain consumption was truly necessary for human health, or whether they were simply the easiest, cheapest, and most profitable foods for the agricultural industry to produce, and so that's what we were told to eat. However this left them open to pedantic attacks like the ones above, even though much of the conventional wisdom has since been overturned.
Unfortunately this early emphasis on higher fat and lower carbs continues to hang like a millstone around the neck of those advocating a more ancestral approach to eating. In reality, those advocating the Paleo Diet were fully aware that these was no one, single, true hunter-gatherer diet. Therefore, it seems unfair to use that as a line of attack as Dr. Pontzer does repeatedly throughout the book, as do many others as well. In fact, I went to Cordain's own Web site and found the following (emphasis mine):
It's remarkable how much current literature and popular diets focus on nutrient ratios, from the “carbs are bad for you” Atkins diet to the 55-65% carbohydrate ratio of the popular food pyramid. It seems one of the hottest topic in nutrition today is the ideal ratio of carbohydrate to fat to protein. But this debate can miss a very important point.
Throughout our entire evolution, our ancestors had no idea what carbohydrates, protein, and fats were. I am certain that when offered a mango, no hunter-gatherer ever muttered the words “No thanks, I’m watching my waistline. I don’t need the carbs right now.” All they understood was what was edible and what was not…
While The Paleo Diet is lower than a Western diet in carbohydrates, it is not a low carb or a high protein/fat diet. That’s because not all carbohydrates, protein, and fats are made the same. A high protein or higher carbohydrate diet can be healthy or unhealthy depending on the foods. The focus of The Paleo Diet is not on ratios, but on eating the foods we evolved to eat. The ratio is a by-product. A healthy Paleo Diet in fact doesn’t have an ideal ratio.
In their 2009 review of plant-animal subsistence ratios of hunter gatherer societies, Dr. Cordain and his team were quick to point out that the plant-animal ratio varied greatly. Societies living close to the equator could get more than 55% of their calories from plant sources, while more polar societies (such as Eskimos) derived almost all of their calories from animal sources.
As a result, the macronutrient ratios could be vastly different. Hunter-gatherer societies ate anywhere between 22-40% carbohydrates, 19-35% protein, and 28-58% fat (though it’s worth pointing out that even those broad ranges are lower carbohydrate and higher protein/fat than the Western diet). So it’s somewhat ironic that despite showing such broad ranges, much of the early criticism of the Paleo Diet was over macronutrient ratios.
In 2002, Dr. Cordain described a sample one-day Paleo menu in one of his early reviews. His sample menu was 23% carbohydrate, 38% protein, and 39% fat. Those numbers have been cited repeatedly by critics of the diet.
But again, they missed the point.
The point of the review was not to establish exact macronutrient ratios. Dr. Cordain could have easily laid out a sample Paleo menu that was higher or lower in carbs, protein, or fat. The point was to show that the sample menu consisted of nutrient dense and healthier foods than a typical Western Diet.
Forget the Macronutrient Ratios - You Are What You Were Designed to Eat (The Paleo Diet)
Not only does Pontzer categorically reject the low carb, high fat, protein-rich depiction of hunter-gatherer diets, he claims that many hunter-gatherer diets are actually quite heavy in carbohydrates, low in fat, and—surprisingly—rich in sugar!
The Hadza, Tsimane, and Shuar populations all get 65 percent or more of these calories each day from carbohydrates (compare that to less than 50 percent for the typcial American diet). It's not just honey and tubers, either. No wonder we've never observed ketosis among Hadza man and women—their diet is about as far from being ketogenic as one could imagine.
Much of this carbohydrate comes from starchy vegetables, like the tubers that the Hadza women often bring home. The other big source of carbohydrate is honey, which Hadza men and women consistently rank as their favorite food.
There's a tendency among diet bloggers an New Age nutritionists to view honey as healthy simply because it's "natural" but there's nothing special about it. Honey (including the stuff the Hadza get) is just sugar and water, with nearly the same percentage of fructose and glucose as high-fructose corn syrup...If carbs—especially sugar—were particularly bad for you, these high-carb cultures should all have diabetes and heart disease. Instead, they have exceptionally healthy hearts and virtually no cardiometabolic disease... (200)
The impressive amount of carbohydrate in the Hadza diet and those of other groups is the mirror image of the 30 percent protein, 20 percent carbs and 50 percent fat energy mix typically promoted as "Paleo." And some Keto and Paleo proponents have pushed this supposed supposed ancestral mix even further. David Perlmutter, author of the popular book Grain Brain, argues—without providing any evidence—that the ancestral diet was only 5 percent carbs and 75 percent fat!2 (B: 201)
Yet again this conflates the Paleo and Ketogenic diets. But leaving that aside, there are some other things to keep in mind here. Given the extreme energetic demands of the hunter-gatherer and subsistence farming lifestyles—as we've seen previously in this series—it would make sense for them to seek out as many carbohydrate-rich foods as possible. It makes somewhat less sense for us, though. And while some hunter-gatherer diets are indeed rich in carbohydrates, just as important is the source of those carbohydrates. Usually they come from starchy foods such as tubers and other vegetables rather than refined flour and sugar. Carbohydrates are in all sorts of foods, including fruits and vegetables (protein, too, can come from a variety plant sources, meaning that a high-protein diet does not necessarily consist solely of meat).
Swedish doctor Staffan Lindeberg is considered to be another pioneer of Paleo diets. He studied the Kitavans of the South Pacific, who were one of the last people on earth consuming an almost wholly traditional diet. He found that their diet was quite high in carbohydrates. Certainly this would seem to invalidate the claim that traditional diets were invariably low carb. But their carbohydrates came from traditional sources rather than bread and refined grains, and—more importantly—their insulin levels were exceptionally low despite their high carbohydrate intake. As Cordain notes, "The Kitavans obtain virtually all of their food from either the land or the sea and have little contact with the modern world. Common western foods such as cereals, dairy, refined sugars, vegetable oils and processed foods are nearly absent from their diets." Dr. Jason Fung writes:
...many primitive societies that eat mostly carbohydrates have very low obesity rates. In 1989, Dr. Staffan Lindeberg studied the residents of Kitava, one of the Trobriand Islands in Papua New Guinea's archipelago—one of the last places on earth where people at a largely traditional diet. Starchy vegetables, including yam, sweet potato and cassava, made up the basis of their diet. An estimated 69 percent of calories were derived from carbohydrates, and less than 1 percent of the calories came from processed Western foods.
Despite this high carbohydrate intake, insulin was very low among the Kitavans, resulting in virtually no obesity. Comparing the Kitavans to his native Swedish population. Dr. Lindberg found that despite a diet that was 70 percent carbohydrate (unrefined), the Kitavans had insulin levels below the 5th percentile of the Swedes. The average Kitavan had an insulin level lower than 95 percent of Swedes. The body mass index of young Kitavans averaged 22 (normal) and it decreased with age. The possibility that increased exercise led to low insulin levels and less obesity was investigated but this turned out not to be the case. (OC: 104-105)
So, while it is clearly possible to eat a high-carbohydrate diet and remain healthy, considering the source of those carbohydrates as well as their glycemic load is just as important, as proponents of the Paleo diet themselves admit. There is good reason to believe that persistently high insulin levels (note the "persistently") eventually leads to insulin resistance, which many believe to be the major driver of both obesity and diabetes. Pontzer does not tell us the insulin levels of the Hadza, but I would suspect that they would be quite low as well.
As for the honey, there may be mitigating factors here as well. Heavy honey consumption among the Hadza (and others like the Mbuti) is apparently highly seasonal, which means that blood sugar levels are not persistently elevated on a 24-hour basis year-round unlike modern diets where sugar is put into almost everything we eat and drink. Plus, they have to work hard for it, walking many miles a day to seek out bee hives. Paleolithic hunter-gatherers would not have been able to access as much honey as present-day hunter-gatherers. It may also be the case that certain populations like the Hadza have developed a degree of resistance to the negative effects of the sugar in honey if they have been consuming it for thousands of years.
Another common line of attack is to point out that people were consuming cereal grains prior to the Neolithic Revolution. What is never stated, however, is how much of a role these grains played in the diet. Nevertheless—regardless of the fact that the originators of the Paleo diet were describing modern-day hunter-gatherers rather than people living in the Paleolithic as I've already described—the "Paleo" moniker allows the “debunkers” to use this as another line of attack. Pontzer himself takes up this line of argument:
...flour and bread are far older than typically thought. Archaeological excavations in Jordan have recently uncovered an ancient oven and charred bread remnants dated to over 14,000 years ago, thousands of years before the emergence of agriculture. The bread flour was made from wild cereals.
While the Jordan find is notable for being the oldest preagricultural site for bread, it's quite likely that similar practices were widespread prior to farming. For example, aboriginal Australian cultures were known to have made breads from wild grains before the introduction of wheat flour from Europe. Hadza women still routinely pound baobab kernels into flour and mix it with water to eat. (B: 197)
It's true, of course. At a site in Italy, grains were being ground into flour as early as 32,000 years ago.In the Near East it's known that food storage preceded domestication by at least a thousand years. Stone Age hunter-gatherers in Britain were eating wild wheat 2,000 years before they started farming it.
But so what? Of course hunter-gatherers exploited wild cereal grains! Everybody knows this. Why would they domesticate a food they did not eat?
In fact, the places where cereal grains played a significant role in the local diet were the very places where cereal grains were domesticated first. Domestication was a direct consequence of the exploitation of wild cereal grains by epipaleolithic hunter-gatherers in places where such grasses were abundant, such as the Hilly Flanks. We know that ancient hunter-gatherers exploited hundreds of different varieties of plant foods, so it would be astonishing if cereal grasses weren't among them. In fact, cereal grains would have been especially valuable resources because, like nuts, they are storable. It's absurd to think that no one ever exploited cereal grains before 10,000 years ago. But, again, as far as I know, no one is saying that!
First, we have no idea what portion of the prehistoric hunter-gatherer diet consisted of these cereal grains. Because they are storable, it makes sense to store up a lot of them for times of scarcity, but that doesn't mean they were a dietary staple. Generally in hunter-gatherer cultures, grains are seen as less desirable and lower status than animal foods, especially fat. We know from animal bones that gazelles and the ancestors of domesticated sheep and goats also made up a major portion of the diet for thousands of years in the ancient Near East. Second, we don't know how many of these grains were used for brewing into alcoholic beverages. Breweries have been found in every region where agriculture began—including in the Americas—dating as far back as 13,000 years ago. Was food the primary reason these grass seeds were being harvested and stored? We simply don't know.
What we do know for certain is that once populations became dependent on cereal grains for their sustenance instead of foraged foods, their health declined significantly—it is beyond any doubt at this point. Epipaleolithic hunter-gatherers in the ancient Near East—or anywhere else for that matter—certainly weren't getting in excess of 70 percent of their daily caloric intake from cereals like wheat, rice, and maize like the inhabitants of the modern world do.
And besides, it's worth noting that today's grains are so vastly transformed from the einkorn and emmer wheat that people were eating back then that they could be considered to be a wholly different food. Most varieties of wheat grown everywhere in the world today are dwarf and semi-dwarf varieties which resulted from the Green Revolution. They grow in soil devoid of nutrients which are made fertile only by copious amounts of artificial fertilizers. Plus, the vast majority of bread today is made from refined flour. Refined flour used to be a luxury, while coarse-grained breads were consigned to the peasant classes. With the advent of the rolling mill this was reversed—refined flour is much cheaper to produce and whole grains are an expensive luxury item. Refined flour is stripped of bran, fiber and nutrients, which are added back in later, or enriched. Refined flour is known to cause spikes in insulin levels. Fiber is known to be protective against insulin spikes. Even that ignores the other artificial ingredients added to most modern breads, including sugar. Subway's sandwich bread—including their whole grain bread—had so much sugar in it that the Irish government classified it as cake for the purposes of taxation. 3
So, in my opinion, the potential consumption of cereal grains by people tens of thousands of years ago is hardly a compelling argument for eating a high-carb diet consisting of breads and cereals today, unless you're stone grinding your own flour from heirloom grains and baking bread from scratch in a home hearth like they were.
Another common line of argument against the Paleo diet is the fact that we've developed genetic adaptations to eating domesticated foods since the Neolithic revolution.
The most well-known of these adaptations is, of course, lactase persistence. Genes that allow us to digest the lactose in milk are usually switched off in adulthood, but in some populations where herding was common these genes have mutated allowing their members to digest the lactose in milk throughout their entire adult lives. And it wasn't always the same genes—several unique mutations have been identified in different herding populations around the world. In Northern Europe up to 90 percent of the population has this mutation indicating their descent from Neolithic pastoralists who migrated into Europe from the steppes beginning around 6,500 years ago. There are some other interesting ones as well, which Pontzer describes:
For example, all humans have more copies of the gene that makes salivary amylase (an enzyme in your spit that digests starch) than other apes, resulting in twice the amount of amylase in our spit and reflecting the importance of starchy foods in the hominin diet. But while all humans living today carry plenty of salivary amylase genes to digest starch, populations vary a bit on the number of gene copies. Cultures with deep traditions of eating more carbohydrates tend to carry even more copies of the salivary amylase gene, increasing their levels of salivary amylase even further and improving their ability to digest starch.
There is also evidence of genetic adaptations for farming. A variant of the of the NAT2 gene, which produces an enzyme involved in several metabolic pathways, is thought to have become more common in farming cultures in response to decreasing levels of dietary folate. Farmers in African and Eurasian cultures, and the resulting shift in the types of fatty acids in the diet, appear to have driven changes in the fatty acid desaturase genes (FADS1 and 2), which are important in lipid metabolism.
Diet and metabolism are such strong evolutionary drivers that we can adapt to almost anything we have to eat. Indigenous groups living in the Atacama Desert of Chile have adapted to the naturally high levels of arsenic in their groundwater, with natural selection favoring a variant of the gene that speeds up clearance of arsenic from the body. The unlucky ones, without the variant, were lost from the gene pool (they were sickly and had fewer kids). (205)
I find this to be an odd line of argument. You could feed any animal a substandard diet for a hundred generations and it would probably develop certain genetic adaptations to it. But that hardly means the diet is ideal for that particular animal, does it? The idea that we should evolve to fit the Procrustean bed of Western-style diets instead of our diets being tailored to suit us is rather bizarre. Dogs and cats have been eating pet chow for a long time, but does that mean that going back to eating natural foods would somehow be less optimal for them? It seems like the burden of proof should be on those who are touting post-agricultural diets as healthier for us than on those who are touting foods that we've been eating for perhaps up to a million years before that.
Plus, as Pontzer himself admits, many of these genetic changes are adaptations to things that post-agricultural diets lacked like folate. Isn't that a tacit admission that agricultural diets are substandard? And if that's the case, why would we continue to eat such a diet because a few of our ancestors developed genetic adaptations to overcome these deficiencies? In the second case Pontzer cites, adaptations to high arsenic levels in the drinking water is hardly an argument for putting arsenic in our water supply is it? The notion that we can evolve to eat anything is bizarre. By this logic, we could eat literally anything—even toxic waste—because we would eventually develop adaptations to it! As Pontzer states, the unlucky ones will become sick and be eliminated from the gene pool. Not exactly reassuring is it?
And besides, small, isolated populations are a poor guide to people living in large, industrial societies today. Small populations evolve much faster than larger ones due to things like the founder effect, bottlenecks, and selective sweeps. Surely Pontzer is aware of these phenomena—he has a doctorate in anthropology from Harvard, after all. Not to mention, nowhere does he say how widespread these adaptations are. If only 30 percent of the population has them, then that means that the vast majority of people do not. He even acknowledges that percentages vary based on ancestral eating habits.
Pontzer once again conflates the Paleo and Keto diets by noting that Arctic populations who eat a diet rich in fat and animal protein and low in carbohydrates have lost the ability to go into ketosis:
Arctic populations have also adapted to eating a lot of meat, but not in a way that most Paleo proponents would predict. Work with Inuit populations in Greenland and Canada has shown that the FADS genes have changed in these groups as well, presumably in response to the high fat content (particularly omega-3 fats) in their diet, which had traditionally included a lot of seal and whale blubber.
With a diet so heavily dependent on meat and fat, these populations are often held up by [Dr. Stephen] Phinney and others as great examples of the benefits of a ketogeneic diet. But remarkably, most people in these groups can't go into ketosis. Instead, they carry a mutant variant of the gene CPT1A that essentially prevents the production of ketones (the "normal" variant of the gene regulates the ketone production in the mitochondria...)
The non-ketogenic variant was so advantageous among the Inuit and other Arctic cultures that it is ubiquitous among these populations today. Paleo-dieters often expound upon the advantages and antiquity of a high-fat ketogeneic diet, but in the populations who have actually lived with these diets for generations, natural selection has pushed back hard. (205-206)
Which is fascinating and might indeed serve as a valid argument against the supposed benefits of ketosis. But again, as we saw above, the Paleo diet does not advocate being in a constant state of ketosis! To some extent, the confusion is understandable, as even people who claim to follow the Paleo Diet often don't really understand what it's really about, as the post referenced earlier explains:
Let me give a real world example of why focusing on ratios over foods can be so dangerous. My wife recently told me about a friend of hers who describes himself as a “Paleo Diet fanatic.” He unfortunately has a habit of lecturing others on their food choices including my wife. Yet, a large portion of his diet consists of bacon, butter, and coconut oil. And he avoids fruit.
His diet may be many things, but I wouldn’t personally call it Paleo. I’m unaware of any hunter-gatherer society that ate butter as a staple and gave the local fruit tree a wide berth.
When my wife asked her friend why he eats the way he does, his answer was all about macronutrients. Carbohydrates are bad for us because they cause cancer and all fats are good because they put us in ketosis.
Addressing both of those points fully is beyond the scope of this article...[but] we can never lose sight of the foundation – eat the foods we evolved to eat. Otherwise, we start snacking on sticks of butter and think it’s a good idea.
Forget the Macronutrient Ratios - You Are What You Were Designed to Eat (The Paleo Diet)
If anything, this is an argument for an individualized approach to diet based on a person's unique genetic history, which is an approach highly favored by proponents of the Paleo Diet. Pontzer neglects to inform us that the genetic adaptations among the Inuit also predispose them to both hypoglycemia and higher infant mortality rates in modern societies. As proponents of Paleo Diet like to say, “Nothing in biology makes sense, except in light of evolution.” Maybe we should listen to them?
It honestly just feels like reaching to me—like throwing everything against the wall and seeing what sticks. It smacks of desperation. Why is Pontzer so eager to dismiss every aspect of the Paleo Diet? Why does he exaggerate their claims and constantly mix up several different diets? I think it goes back to what I said previously—"serious" scientists don't lend credence to popular fads or else they would lose their reputation. So he starts from a position of hostility instead of looking for points of agreement and things to learn. I am coming from the opposite perspective.
The irony in all this is that Pontzer himself tells us that both low-carb and ketogenic diets are effective for weight loss! In fairness to Pontzer, he does say that if a diet is working for you, then you should stick with it regardless of the underlying mechanism as to why it works.
In conclusion, you can certainly nitpick, exaggerate, belittle, and make pedantic arguments against the historical and ethnographic accuracy of the Paleo diet and poke fun at some of its more extreme adherents, but I think it makes more sense to focus on the big picture of ancestral health and see what it has to tell us. Some aspects of the diet might work, even if they are not a totally accurate representation of what people ate, now or in the past. Eliminating grains can help us cut back on our calorie consumption and keep our blood sugar levels stable, regardless of what people were eating in the Paleolithic. Protein and fat do help our satiety levels. And besides, the Paleo diet is ultimately as much about what hunter-gatherers don’t eat as what they do: refined flour and sugar, industrial seed oils, soft drinks, candy bars, and other ultraprocessed shelf-stable foods:
...of course there is no one true ancestral diet with a strictly curated, specific list of dietary DOs and DON’Ts. Humans have managed to populate every barely hospitable nook and cranny of this planet. If living things grow, slither, crawl, flap, swim, or otherwise reside there, we will set up shop in order to eat them.
However, patterns do emerge. First, there’s the aforementioned total absences – seed oils, sugar – plus a dearth of cultivated grains. Wild versions of grains existed (after all, the first agriculturalists needed something to domesticate), but there’s little evidence to suggest they were major parts of most early human diets.
Second, there’s animal consumption. We just love eating sentient, mobile organisms. There’s never been a traditionally vegetarian culture, and every hunter-gatherer population ever studied consumes animals.
Third, there’s plant consumption. Plants are trickier than animals because they keep fighting back after you’ve killed (and sometimes cooked) them...
There were no “ideal foods“? Okay. That’s not the point. I’m just establishing that there were simply “dietary patterns that shaped the metabolisms, nutritional requirements, endocrine systems, and brains of the walking, talking, loving, pondering collectives of cells and microbes we call ourselves.”
I don’t know about you, but it seems like examining these dietary patterns might offer helpful clues for modern humans currently embroiled in a classic case of evolutionary mismatch. Mismatches are very interesting when you’re a detached academic observing the trajectory of another species, but on the ground level, to the organism experiencing it, mismatches lead to diseases, pain, and suffering. They’re awful.
We Don’t Know What Constitutes a True Paleo Diet (Mark’s Daily Apple)
Next time (since I'm out of room) we'll take a look at what humans really were eating in the Paleolithic.
There is an entire book called Paleofantasy which is dedicated to making these kinds of bad-faith arguments.
I checked out this book (Grain Brain) from the library. The claim in question is not in the text but featured in a pie chart on page 27. He's right, of course, we can't make such claims about the "ancestral diet," whatever that means, and no source is given for the data. But the book is primarily about the effects of gluten on brain health, is written by an MD, and—importantly—has nothing whatsoever to do with the Paleo Diet. The term "Paleo Diet" isn't even used anywhere in the text.
It also used to contain a chemical used to make Yoga mats in it, which I'm pretty sure was not in Paleolithic bread (and would be remarkable if it were).