Primitive Nutrition 2:
I, Copernicus, Part I
It is my opinion that at its root the Paleo diet idea is just another version of a fallacy called the appeal to nature. The Fallacy Files website shows us how this fallacy can appear in discussions of diet and lifestyle. It also makes the point that something is not necessarily better just because it is considered natural.
Many primitive cultures have practiced cannibalism.
There exists archaeological evidence of our hominid ancestors practicing cannibalism nutritionally. So is cannibalism natural? Does our genome require us to eat each other? I certainly hope not.
I'm a vegan who eats a lot of fruit so I think it's only fair for me to give you an example of this fallacy in some other vegans who also eat a lot of fruit. This story is about a fruitarian couple who were put on trial for neglect in the death of their daughter. These people in all likelihood believed they were putting into practice the perfect natural diet. If you are a Paleo dieter, I'll bet you have no trouble seeing how that belief blinded them to reality as their daughter withered. They had plenty of warning signs, but they had this idea stuck in their heads so they missed them. Ideas like this can be powerful.
The Paleo diet is often defined in absolutist terms that might resemble the rhetoric of a radical fruitarian. It's "the optimum diet for the human animal." How convenient! It's optimum by definition! If accepted literally, this rigid belief has the potential to blind someone to any flaws of the diet, just as the fruitarian couple was blinded. The Paleo writings I've seen are laced with this sort of dogmatism.
In this excerpt from The Paleo Diet, Loren Cordain uses some mind-closing absolutist language as he states that his diet is the one and only diet that ideally fits every person. It is unusual to hear someone who calls himself a scientist speak in such a dogmatic way about an opinion that is not widely shared by other scientists. It's also unusual to see a scientist so strongly embrace the appeal to nature fallacy.
Scientists rarely engage in absolutist language when they propose new ideas because they know there is always the possibility new data will force them to reconsider.
They know this is an inherent strength of scientific reasoning, as all ideas are open to challenge by better ideas.
When Cordain says there is a one and only diet ideally suited for all humans, a diet fixed in a time and place in the distant past, he is essentially saying that in a practical sense, there is no possibility of progress or improvement in nutrition. This is quite an extraordinary claim before we even consider the substance of it.
The use of absolutist rhetoric is avoided by scientists for obvious reasons. Take for example his statement that 500 generations ago every human on Earth ate the Paleo way. 500 generations is roughly 10,000 years. All one would have to do to undermine this statement would be to find just one example proving people ate from his banned foods list before that.
Here you see that in fact humans were eating quite a lot of legumes far earlier than that, between 65 and 48 thousand years ago. What does that do to Cordain's thesis? Should we now say instead that legumes are required by our hunter gatherer genome? But I thought the Paleo diet as described in his book was the one and only ideal human diet!
This is why scholars who wish to be taken seriously do not make arguments that can be nullified with only one data point.
He also uses the "design" word, as in you were designed to eat this way. Here we have a scientist whose whole argument is based on evolution who is seemingly unaware of the teleological argument, perhaps the first and most enduring argument against the idea of evolution since it was first proposed by Darwin and Wallace.
Of course, Cordain is not saying a supernatural creator designed man. He is using the less loaded term "nature," instead. Either way, anyone familiar with evolution should know that just because something in nature appears to be designed, that does not mean it was designed.
Here he veers more recklessly into this fallacy. Humans were meant to be meat eaters? Who meant that for humans? Nature? What does that mean? What else does nature mean for us? And how can Loren Cordain tell? Are we also meant to have parasitic infections? This may seem like a quibble but this language is utterly alien to those who study evolution. So why does he talk like this? He needs an absolutist view to make his diet ideas work. He needs you to feel that you have no choice but to buy in on Paleo all the way. The choice has been taken out of your hands. You simply were meant to eat meat and avoid grains and that's that. It is etched indelibly in your genome, so there is no need for further questions.
The idea that we are meant to be something or not, or that we are designed in any sense, implies a creator. This is a religious argument that is not sustainable in a scientific context. It assumes there can be perfection in nature, which I will show you later is a troublesome concept.
To set Cordain straight I will invoke an expert no less than Richard Dawkins, who makes clear any appearance of design in biology is an illusion.
Dr Cordain, there is no design in evolution.
I'm going to focus now on this online publication called The Protein Debate. In it, Loren Cordain and T Colin Campbell of The China Study fame go head to head on the topic of human protein requirements. The protein discussion is not as interesting as the statements of philosophy from each man. Cordain lays out his beliefs in a way that I find highly revealing of the sort of thinking that led to the Paleo diet.
Read blog posts like Robb Wolf's about The Protein Debate and you will see that the Paleo dieters think Cordain bested Campbell in decisive fashion. I have not seen any Paleo dieters address the concerns I will raise here, which I take to mean they are in at least general agreement with him. This should be no surprise because without these beliefs, the diet philosophy falls apart. Wolf makes it clear once again that I have apparently taken on a real challenge in criticizing the Paleo idea, putting me in the same category as flat earthers in his estimation. He likes Cordain's statements in the debate enough to do a big copy and paste job of them, as you see to the right. Can you blame him? Remember, Cordain is one of the world's most renowned scientists.
To the left you see a cartoon of Wolf, presumably finding eternal truths about the evils of evolutionarily novel foods in his beaker. These guys are super sciency. Wish me luck!
I'll start my look at The Protein Debate here, a few paragraphs into Cordain's first essay. Cordain seeks to draw a contrast between nutrition science and other sciences by portraying it as immature. So immediately, the exercise physiologist and primitive diet researcher has condescended to an entire field of scientific inquiry.
In his second essay in The Protein Debate, Cordain further reveals his contempt for nutrition science, with multiple uses of the word "discoveries," which he sarcastically surrounds with quotes each time. He seems to think that if something discovered has always existed, the significance of its discovery is somehow lessened. It’s like he is saying, "So what if you guys discovered we need vitamin B12? If you understand the genome the way that I do, you don't need to bother discovering these various and sundry little nutrients." Once again, Cordain sees a field of science as a finished business. How unusual for a scientist to express this attitude toward scientific discovery!
If we return to the previous slide at the left, his first example of what he calls a well-developed discipline is cosmology, with its Big Bang. Do cosmologists have a similar view of, quote, "discoveries"?
Cosmology is a strange candidate to prove Cordain's point that a mature science needs a universal paradigm. He says in the paragraph to the right that without an overarching template, there is disagreement and confusion in a discipline, which he feels is a big problem. None of that in cosmology, right? If you were about to ask, yes, he later uses the phrase "unified theory."
And there it is. Cordain evidently thinks cosmology has a unified theory, while nutrition does not. That is a doozy, isn't it?
If you are unaware, there yet remains to be described a Grand Unified Theory, or a Theory of Everything, that would resolve the contradictions between quantum mechanics and general relativity, and in so doing explain the Big Bang. The lack of such an understanding has left some rather huge gaps in our knowledge of the cosmos.
For example, the ordinary matter we know and understand comprises less than 5% of the observable universe. All the rest is quite mysterious.
And it has been proposed that there may be multiple universes beyond the known universe. These are some pretty big blind spots in cosmology.
How did Cordain decide cosmology was a mature science with such enormous questions left unexplained? Would he dare call physics an immature science? Does he think astrophysicists are gratified or embarrassed when new discoveries are made? After all, their science is only trying to explain things that already exist.
In the paragraph on the right, Cordain says that nutrition has a chaos problem, with disagreement and confusion in the discipline. This is actually not the case. The world's major health institutions agree on most of their recommendations. Confusion mostly just happens at the bookstore and online due to fad diet promoters like him.
Here’s another strangely revealing quote by Cordain. He says, "When the data consistently do not support the hypothesis, it is inappropriate to manipulate and selectively use flawed data to continue to support the erroneous hypothesis." Then he oddly provides a reference for that statement. So researchers shouldn't cherry-pick or use bad data? Is that so controversial he needs to provide a citation? I think it's odder still what that footnote is. Notice it's a whole book. Does he think this is the one resource that, when read in its entirety, will convince people not to distort data? No. This reference tells us he is driving at something else. He thinks he has a big idea.
Here is the Wikipedia page for the book he has referenced, called The Structure of Scientific Revolutions. He has just taken us on a detour into the philosophy of science, reminding us of Thomas Kuhn's idea that science advances through periodic profound revolutions, or paradigm shifts.
Each revolution entirely replaces the last because they are in conflict and cannot be reconciled.
An example of this would be the Copernican Revolution, which placed the sun at the center of the solar system, rather than the earth. Because he chose this reference, Cordain does indeed seem to have a grandiose appraisal of his hypothesis.
It is worth pointing out here that Kuhn's ideas are hardly universally embraced.
I have to wonder, what is the old paradigm that the Cordain revolution would replace?
The USDA MyPlate graphic? I think Kuhn might have been underwhelmed by this revolution.
Stay with me for Part II of I, Copernicus. I have lots more on the Protein Debate just ahead.
Primitive Nutrition 3:
I, Copernicus, Part II
Let's go back to look at another footnote, number 11 on the top right. Cordain is citing someone else's work to support his assertion that nutrition science is immature. Who else would say such a thing?
Here's the article he is citing. I'm not sure it supports his opinion about nutrition science or his Paleo Diet very well.
So does it say nutrition science remains immature? Not at all. Here you see the single appearance of the word nutrition in the article, but it's about how poor nutrition affects a fetus.
This article actually is a great argument against the design fallacy. It gives a litany of examples of health challenges arising from our lack of coherent design. As I have stated, the Paleo Diet concept is totally invested in the design fallacy, so this article is bad news for Cordain, whether he recognizes that or not.
Recall from his book his belief that there can be such a thing as an ideal diet for us. There can be only one. Our genome is that coherent.
This is echoed in the rhetoric of other Paleo promoters, like this podcast host. Who wouldn't want to believe his warm-and-fuzzy that humans are not broken by default? By implication, the belief seems to be that if only we eat and live like a stone ager, we will be happy and healthy and trouble-free. This is a childish belief. Mature adults are accepting of the imperfections in life.
The next time someone suggests that humans aren't naturally conflicted, incoherent, or somehow broken, remember the Online Mendelian Inheritance in Man database, where all the thousands of diseases of genetic origin are catalogued.
Or just listen to this song.
Perfection is a pretty elusive concept in science. The two nearest examples of perfection I can think of are merely shapes. Here are the balancing gyroscopic spheres in the satellite Gravity Probe B. These are the most perfect objects created by humans, as far as I am aware. They are not perfect spheres, but darn close.
The most perfect object I can think of in nature is the electron, which is indeed fantastically round.
Now contemplate the human genome, with its more than 3 billion base pairs. What chance is there it could be perfect, as in free of contradiction? Not much, folks. I’ll explain that further a bit later.
For now let me just offer this as an example of why perfection is such a difficult idea to pin down in nature. You can pause the video to read this classic case involving moths. As their environment changed, their different colors gave them different levels of fitness. The circumstances of all creatures change, not just moths. Evolution just has to produce results that are good enough to keep going.
Let's return to the Protein Debate. Cordain believes our dietary requirements are encoded in the genome in some specific and knowable way, so specific that you could capture it in a diet book.
Here is a paper Cordain published along with a cardiologist that makes explicit his belief that a hunter gatherer lifestyle is embedded in our genome.
For a different viewpoint, have a look at what T Colin Campbell says about nutrition in The Protein Debate. He rejects what he calls reductionism in nutrition. He is not interested in responding to all the individual studies of particular nutrients that Cordain cites. Instead, Campbell believes nutrition plays out in a complex biological system. I think he has a point.
Campbell likes a holistic approach to nutrition, which is not such a strange idea in other biological sciences.
This approach recognizes that the whole is more than the sum of the parts, and that complex interactions give rise to emergent properties.
The recognition of the existence of complex adaptive systems is not exclusive to biology, either.
This applies to the genome and to nutrition. Proteomics, or the study of all the proteins produced by genes, is a concept necessitated by the limitations of studying just the genome.
The proteome is much more complex and challenging to study than the genome.
It is understood that proteomics is highly relevant to nutrition research.
The proteome isn’t the only layer of complexity over and above the genome, however. Here to the left are more, including the transcriptome and the metabolome.
And they, too, are understood to add complexity to nutrition science.
Cordain is aware of all this. Here on his own site when asked whether his view of the genome as the sole determinant of our nutritional needs can be reconciled with nutrigenomics, he simply answers yes. That's it. He then just regurgitates the programmed Paleo article of faith about how our nutritional needs are in our caveman genome, and that means no grains. I don't feel enlightened at all by this answer.
Just for fun, let's ask how without a big idea like Paleo or veganism to simplify things we could use nutrigenomics to create concrete, science-based, personalized nutritional recommendations based on the subtleties of the genome and everything else. Pause the video and read this slide if you like. You’ll see that reaching these goals would be a monumental task.
You see, in their own ways, Campbell and Cordain are both rejecting this approach. They are both rejecting reductionsim in favor of big themes. Cordain just wants to have it both ways. He cites lots and lots of studies, but he also ignores far more studies, the studies that don’t help his agenda. Actually, Campbell’s views are better supported by the literature than Cordain’s are. That will be made clear throughout the Primitive Nutrition Series.
Cordain wants a big unifying principle to harmonize every finding of nutrition science. This is an unreasonable expectation.
Scholars outside the bio sciences sometimes wonder why the workings of life don't adhere to rigid universal laws. The answer, Cordain should know, is found in evolution itself, which is inherently random and undirected.
Cordain's expectation that the body’s metabolic processes should be easily simplified does not square well with a modern understanding of biological systems. It is understood that homeostasis relies on probabilistic feedback loops. Short-term observational studies or studies which focus on one or two outcomes can’t demonstrate the full consequences of dietary patterns, yet short-term studies are all that low-carbers like Cordain have to offer.
I'll throw this up here to remind us of the scientific method. An honest application of Cordain's requirement that all data be entirely clear and coherent, without any appearance of cherry-picking, would place all nutrition science trapped in a repeating loop of constructing and revising hypotheses without ever reaching conclusions, as there is always some little study out there that contradicts the preponderance of the evidence. This is not only a result of the complex interactions our bodies have with food. It is also a result of variations in study designs and, naturally, the biases of the researchers.
Let's ask whether Cordain's idea of an evolution-based diet as a unifying theory of nutrition even meets the basic definition of a theory.
In these definitions a theory must offer a comprehensive, well-substantiated explanation of some aspect of the natural world. It must be so powerful it not only accounts for everything already known, it must have predictive value for future discoveries.
It also should be falsifiable. If it isn’t, it really isn't scientific. If you pause this to read the bottom section, you'll notice the distinction made between a hypothesis and a theory. At best, the Paleo nutrition idea is a just a hypothesis.
Falsifiability is a big problem for this hypothesis. Let me show you why. One of the arguments put forth by its promoters is that the diet is, in the course of digestion, net base-, as opposed to net acid-, producing. In contradicting that, this paper established what should have been obvious: that a diet that relies so heavily on meat will be net-acid producing. Hypothesis falsified, right, Dr Cordain? Time for a retraction?
Nope. Cordain simply responded that this paper somehow served to advance the original Paleo idea. Rather than admit he just got nailed, he tries to co-opt the paper's critique, and he hopes you won't notice. I included a few additional sentences that reveal his disingenuousness if you want to pause and read this. Standard Paleo blather is regurgitated, of course. An assertion is made that health problems developed as a result of the inability of evolution to keep pace with new foods. There is once again a reference to a whole book. Then you see he conjures imaginary unbiased observers who - naturally - would agree with him.
This is a handy technique, isn't it? I could say unbiased observers would say Loren Cordain is just a slippery diet salesman but I won't because that's would sound like I'm quoting an imaginary friend. His point is people are unhealthy because they followed the dietary advice of the major health institutions. Now does that ring true to you? How many obese people do you know who are religiously following the DASH diet or the USDA food pyramid?
At the end he shakes off the blow he just took from that paper and instead reasserts the need for a paradigm shift in nutrition, which he says will require mental agility. I'll give Cordain that. He is certainly mentally agile.
Pseudoscientists start with an idea they want to prove, and then backfill supporting data as it suits them. We have just seen one way the Paleo fad evades falsifiability. I will show you more later. It is my contention that Paleo diet promoters consistently fall into this pseudoscience pattern.
Let's now consider the idea of predictive power, a component of the definition of a proper theory. What does a Paleo diet theory predict, exactly? How would this be testable? If you think the answer is seen in the health of observed hunter gatherers, I will show you how it fails that test in another section. If the answer is the archaeological evidence of the diets of real ancient Paleolithic hunter gatherers, that is not truly testable. I’ll cover that as well. If you think this idea has been proven in controlled trials I will show you that their studies fall far short of any standard of proof. In fact, I will show you that there is much better evidence supporting diets that oppose the Paleo Diet.
Make no mistake, I am not questioning the fact of evolution. The theory of evolution has indeed been verified both experimentally and through prediction. Here are examples of the fossil finds and genetic evidence that it was used successfully to predict. Visit this site and you will find no references to the predicted benefits of cutting out lentils or eating lots of meat.
This is a nice explanation of how predictions work, and how they don't, within evolutionary theory. One cannot predict with any accuracy how the evolution of organisms will play out.
So what does this all add up to? Before we even get into the specifics of the Paleo diet, we can see its principal promoter expects to transform a field of science which he doesn't seem to understand, and we see he holds the ideas of others to standards his own ideas could never meet.
Next, I'll show you that the Paleo diet idea is so vague, it's practically useless.