A couple of weeks ago, Leigh Peele, a well-known nutritionist who often appears on the FitCast, spoke out in a detailed blog post against the Paleo Diet. It isn’t really a goal of my blog to talk about diet but since I haven’t seen anyone else respond, I do feel that there is a need to respond and point people towards the work of Loren Cordain, which I feel is more than capable of withstanding all of the criticisms that Leigh made.
What is more, Leigh’s article forced me to be a lot more critical about my own beliefs, which is always very valuable, and to that extent, I am very grateful that Leigh took the time to compile this argument.
Leigh was good enough to summarise her points at the foot of the article, and I reproduce them here, along with my references to Loren Cordain. Any errors, mistakes, misunderstandings of Cordain’s work or other general ass-hattery are my own:
#1: Extremely small amounts of information are known about the actual Paleolithic Period
This may or may not be the case but I feel quite strongly that just because something is difficult doesn’t mean we shouldn’t try to achieve it. Moreover, I would suggest that Loren Cordain, as the world’s leading expert on the Paleo Diet, would be one of the people we should turn to in order to understand exactly what the diet comprised. Let’s move on.
#2: Our closest counterparts existed towards the Upper end of the Paleolithic Period
I think we can all agree that our closest counterparts in the Paleolithic Period are going to exist towards the end of it. But if it is a fundamental principle that we should be eating what our closest counterparts ate, then we should be eating what our parents ate, right? Err, no. Have you seen what my dad eats?
I think we all agree that the key to what we should eat is what we have adapted to eat. Adaptation occurs quickly in response to what came most recently and it occurs through very long periods of doing the same thing. We place weight on recent events and we place weight on very long periods of time. And this is where Leigh seems to have a different view of how long the Paleolithic period is from other people, which might explain why she seems to believe that the very long periods of time we are talking about seem less important to her.
Leigh says in her article that: ” the full Paleolithic age ranges over 250,000 years by some estimations.” On the other hand, Loren Cordain says: “remember that the Paleolithic period extends from the first appearance of stone tools (2.6 million years ago) until the beginning of agriculture 10,000 years ago.” That’s quite a big difference.
#3: Contrary to popular belief, grains were a part of the Upper Paleolithic Diet
This is most likely the big issue for most people. But, as Leigh notes, the big noise that we are hearing about at the moment is just journalism finally catching up with what the researchers have known for a long time. This is fortunate, since it allows us to see what Loren Cordain has to say on the matter.
The only significant claim that grains were part of the Paleo Diet is found in a study published in Nature called “processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis“. Loren Cordain responded in his page on Paleo Diet Rheumatoid Arthritis saying: “the recent paper in Nature… in no way changes the basic premise that Paleolithic hominins rarely or never consumed cereal grains.”
In the same section, Cordain goes on to make several key points: “first, nowhere else in the world except for the Levant is there any evidence for cereal grain consumption at this early date – not in Europe, not in Asia and not in Africa. Secondly, because cereal grains were not domesticated until 10,000 years ago, grains could have only been consumed seasonally a few weeks out of the year, and would not have been staple foods… Finally, 23,000 years ago, although it may seem historically remote, represents less than 1.0 % of the time hominins have resided on earth. Consequently, for 99% of the evolution of virtually all hominins, cereals grains were not part of the diet.”
To another study, published in Science, called “Mozambican Grass Seed Consumption During the Middle Stone Age“, Cordain has responded at Primal Wisdom, saying “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 (the above study published in Nature) still represents the best earliest evidence for grain consumption by hominins.”
Regarding the studies that Leigh cites regarding storage bins, I note that these refer to granaries produced 11,000 years ago, at the dawn of agriculture, which I don’t see as relevant for Paleolithic times. Similarly, the reference to wild grasses refers to seeds consumed 23,000 years ago, which again is small in the context of the full Paleolithic period, although this is a fascinating study to look at and I am grateful for her for bringing it to our attention.
#3b: Ever since farming and grains became a popular part of our life, we have been growing in health and ability
I added an extra point here because Leigh goes into this issue at some length in the main article and then doesn’t mention it in the summary points. Moreover, I think that if this assertion is true it has very wide-ranging implications. It’s also a great topic to get stuck into!
Leigh notes a study that covers dental indicators of health and stress in early Egyptian and Nubian agriculturalists. Leigh argues that this is evidence that agriculture actually improved health, although the study is more equivocal. The study actually notes that “the period surrounding the emergence of early agriculture in the Nile valley was associated with high stress and poor health”, which is exactly the opposite of what Leigh is claiming. Only later on did this trend start to reverse. So this study does not seem to be cast-iron proof of her point.
On the other hand, Loren Cordain notes that “whenever cereal-based diets were adopted as a staple food, replacing the rich variety of wild animal and plant based foods of hunter gatherers, there was a characteristic reduction in stature, an increase in infant mortality, a reduction in life span, an increased incidence of infectious diseases, an increase in iron deficiency anaemia, an increased incidence of osteomalacia, porotic hyperostosis and other bone mineral disorders and an increase in the number of dental caries and enamel defects.” In the article cited, all of these points are given footnotes to various studies supporting these observations.
And let’s not forget that there are scientists who believe that the regular consumption of alcohol is what caused us to begin collecting and later farming grains…
#4: Today, our average lifespan is over double of that of Paleolithic man
As someone who was forced to do a certain amount of statistics at university, this really bothers me. Comparing the average (i.e. mean) life expectancy of humans at varying times is irrelevant unless you adjust for infant mortality (and violent death, if possible). Therefore, suggesting that we live longer now than in Paleolithic times because of better nutrition on the basis of average life expectancy is not valid. This is covered in Loren Cordain’s Paleo Diet Basics.
#5: Diseases and our bodies evolve quickly from century to century, let alone over the course of 40,000+ years
I would be interested in hearing more about this but I am peripherally aware of how evolution proceeds. Some things (like having two legs and a head) were fixed quite early on in the development of hominins and other things (like hairlessness and opposable thumbs) were fixed later. The earlier things get fixed, the harder they are to change. I would be surprised if our ability to process nutrients was fixed as late as the Neolithic period but I would be intrigued to find out otherwise.
Loren Cordain notes in his Paleo Diet Miscellaneous that “our genome simply has had insufficient time to adapt to the foods ushered in during the Neolithic (fatty meats, dairy products, whole grains and salty foods).”
#6: Obesity and self afflicting diseases are not going to be solved by a fad diet, but by looking at the physical and psychological effects of life we live now, not 40,000+ years ago
Loren Cordain says, in his Paleo Diet Basics, that “the Paleo Diet is the unique diet to which our species is genetically adapted. This program of eating was not designed by diet doctors, faddists, or nutritionists, but rather by Mother Nature’s wisdom acting through evolution and natural selection.”
#7: Even though there is speculation, literature points to carbohydrates making up at least 50-55% of the Paleolithic Diet
In a recent paper entitled “estimated macronutrient and fatty acid intakes from an East African Paleolithic diet“, Loren Cordain sets the macronutrient ratios at approximately:
- Protein 25 – 30%
- Fat 30 – 40%
- Carbohydrate 40%
Firstly, I note that the range of 50% – 55% referred to by Leigh therefore looks too high. Secondly, I would note that Cordain is at pains to draw a strong distinction between the Paleo Diet and any low-carb diets. In his Paleo Diet Basics, he says “this nutritional plan is totally unlike those irresponsible, low-carbohydrate, high-fat, fad diets that allow unlimited consumption of artery-clogging cheeses, bacon, butter, and fatty meats. Rather, the foundation of the Paleo Diet is lean meat, seafood, and unlimited consumption of fresh fruits and veggies.”
I would also note that many of the popular writers on the Paleo Diet that Leigh denigrates have themselves noted and challenged the tendancy of a vocal minority to equate the Paleo Diet with low-carb diets. Matt Metzgar recently challenged the assumption in a very interesting post called where are the low-carb hunter gatherers?
#8: Popular writers and marketers of the Paleolithic Diet do not use proper research and data and commonly seem to cherry pick research
Here, I think that Leigh has confused popular writers on the subject of the Paleo Diet with the real thing. Loren Cordain is a peer-reviewed scientist and I do not think that anyone in those scientific circles is accusing him of failing to carry out proper protocol.
#9: There are extremely beneficial, researched, health benefits to whole grains and their use in the large population. This is not limited to digestion and diabetes
While there may be studies to support this claim, it is also fairly straightforward to support an opposing viewpoint. Consider the following articles (which are all either reviews of studies or from highly reputable sources):
- Cereal grains: humanity’s double-edged sword Loren Cordain explains why cereal grains are a bad thing. I could probably have stopped here but I was on a roll so I thought I would carry on and provide a few more links.
- Why does wheat cause arthritis? Dr William Davis explains how wheat causes arthritis through the damaging effects of glycation, it’s acidifying effect and it increase in visceral fat.
- Whole grains give you cancer? Conditioning Research notes that a recent study into prostate cancer showed that there was a “positive association between dietary intake of whole grains and total prostate cancer”.
- Medical Acceptance of the Celiac Pandemic: Is the Decades-Old Ridicule Ending? Coralee Thompson M.D., writing at Phil Maffetone, notes that “those carrying the gene for celiac disease, about a third of the population, can easily bring out the condition. Just eat enough wheat and you can trigger the celiac gene to express itself, resulting in the illness. This is just what’s been happening. Since 1950, the incidence of celiac disease has increased by almost 500%.”
- The China Study on Wheat and Heart Disease Denise Minger has carried out extensive analyis on the China Study data and found that “wheat flour… correlates significantly with hypertensive heart disease and stroke (and) coronary heart disease.”
- The Poliquin Protein Primer (produced by Charles Poliquin) quotes Jack Weatherford’s book “Genghis Khan and the Making of the Modern World”, saying “The Chinese noted with surprise and disgust the ability of the Mongol warriors to survive on little food and water for long periods…. The Mongols consumed a steady diet of meat, milk, yogurt, and other dairy products and they fought men who lived on gruel made from various grains. The grain diet of the peasant warriors stunted their bones, rotted their teeth, and left them weak and prone to disease.”
#10: While the dogma behind the Paleo Diet is not healthy, the basic nutritional principles seem to be sound, but could lead to problems of improper energy fueling or eating disorders
In the sense that Leigh uses the word, dogma is what people use to describe other people’s claims to truth that are not founded on scientific research. As we’ve noted above, there is plenty of genuine research being done on the Paleo Diet but I don’t think that Leigh really engaged with any of it. In fact, I don’t recall reading any reference to Loren Cordain in her article, which is a bit like writing about Catholicism without referring at any point to St. Peter.
And if the concern is for fueling exercise, it may be instructive to read Loren Cordain’s page on the Paleo Diet for Athletes, where he discusses how fruit and vegetables provide carbohydrates for energy and also how becoming fat-adapted is beneficial for making better use of this macronutrient.
#11: Using the term Paleo in regards to grain or carbohydrate restriction appears to be factually incorrect
Cordain’s responses to the issue of grains are noted above in point (3) and the point relating to carbohydrate levels is valid, but irrelevant, as is noted in point (7).
That’s all folks. Thank you for your time. Normal service will be resumed tomorrow.
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