TPNS 17-18: Phytophobia

Primitive Nutrition 17:
Phytophobia, Part I

Loren Cordain is a longtime believer in the idea that some foods are bad for us because of what he calls their "evolutionary discordance."  Cordain gives the impression that grains and legumes are practically toxic because they were not eaten in the distant past.  I think the concept of evolutionary discordance is worthless in nutrition.  We can see through nutrition science what effects foods have without needing this idea.

I can’t resist starting with an obvious point.  The cultivation of crops that led to an enormous and sustained population explosion was a successful adaptation.  Evolution weighed in on this  long ago.

Making a case that a food is good or bad because it's novel is not easy.  In this slide, one of the model cultures in the Paleo world, the native Australians, consumed at least 800 different plant species.  Could they have really evolved special tolerances for each and every one of them?  Or did they just figure out what plants they could eat through trial and error?  You know the answer.  Hunter gatherers pass on their knowledge of the plants around them from one generation to the next.

Here are some fruits native to North America.  Should someone in Korea be concerned that a blueberry is evolutionarily novel before eating one?

What about invasive species?  This wild pig is not native to North America, but his species seems to be doing pretty well here anyway.  How much of what he eats here is evolutionarily novel and what price is he paying for it?  Notice that wild pigs are adaptable, generalist, opportunistic omnivores who can live in a variety of regions and climates.  Does that remind you of another species?

This article about our hominid ancestor Australopithecus africanus has a great line about diets in generalist species.  They do not have to do many things well, they merely have to do many things adequately.  This applies to us, too.

If you don't understand toxicity, there are a lot of things you can worry about unnecessarily.

You could even stigmatize water.

Toxicity is determined by its dose response.  The question with toxicity is, at what dosage does the substance in question induce a toxic response? In toxicology, the saying is "the dose makes the poison."

This standard is applied to food as well.  Notice that every food component can be a potential hazard..

Virtually all natural foods contain some toxicant.  They are either neutralized in processing or they are handled without ill-effects by our bodies through biotransformation.

It is unavoidable that you will ingest some small amount of toxicants in food.

Interestingly, we need the received knowledge of our ancestors, too, just like Aboriginal Australians did.  You can't just look at a plant and tell whether it's poisonous.

Humans have thrived as a species because of this received knowledge, and through our development of technology.  Today we process the demonized soybean, for example, to neutralize antinutrients.  We also have cultivated our plants to have less of these toxins today than in the past.

We've been processing otherwise toxic plants to make them nutritious for a long time.  This is part of what makes us human.

Give plants a break.  How could an organism evolve to be entirely nutritious for another organism?  By what mechanism would that be possible?  Fruits are about as close as you can get to a category of plant food that might have evolved to be nutritious for an organism that eats it.  Plants can use animals to assist in dispersing their seeds by producing fruits they like to eat.

However, this relationship isn't so simple.  Of course, some berries can be poisonous.  Moreover, while you might think that plants would benefit more from frugivores than granivores, or seed eaters, that is not necessarily true.  All that matters in evolution is what the genome wants, and that is reproduction.  The plant itself is just the vehicle.

Plants have secondary compounds that can be either good or bad for us.

The plants we tend to use have in a sense coevolved with us, as we have selectively bred cultivars that are preferable for our purposes.  We also are generalist feeders, so we have evolved to be able to consume a variety of plants.

Our taste helps us discern whether a plant is safe and nutritious.  We have this in common with our primate cousins, who can be highly selective of what they eat.

And like us, as you see in this fascinating study, they also rely on others' experience to determine whether a food is safe for them.

Humans have always had exposure to potentially toxic plant compounds, and that has influenced how we evolved as a species.

Natural plant toxins are a problem for the cattle the Paleo dieters like to consume, resulting in major economic losses to the meat industry.  It seems to me this would be a bigger problem for grass fed beef.

The Tomato Effect describes the rejection of efficacious treatments for illogical reasons.  It seems apropos to mention here because of the history of the name.  Tomatoes, a plant native to South America, were at one time considered poisonous in North America even as they were avidly consumed in Europe.  Europeans benefited from a highly nutritious evolutionarily novel food, while North Americans missed out because they were afraid of them

You can pay for Loren Cordain's opinion of whether tomatoes pass his leaky gut test.

Or you could save some money and just trust your taste buds, all responsible health institutions, and the collective experience of humanity and just not give it a second thought.

In the next part of the Phytophobia section, I'll show you some other examples of this silliness.

Primitive Nutrition 18:
Phytophobia, Part II

Another example of a scary plant food is the humble potato.

They fail the leaky gut test in Paleo like a lot of other healthy foods.  The Paleo world is amazingly fixated on leaky gut and autoimmune disease.

The problematic compounds in potatoes are called glycoalkaloids. A concern with them in this study is that they might enhance the uptake of allergenic molecules.

Allergies and autoimmune disorders are known to be closely related.

Eastern European nations are the biggest consumers of potatoes.  Are their immune systems on the fritz?  I couldn't find any information generally regarding autoimmune problems in the world potato leader, Belarus, as the after effects of Chernobyl dominate the literature on that subject.

I found some information about allergies there, though.  Allergies occur at a very low rate in Belarus.  Shouldn't there be an allergy problem in the most potato-loving country in the world from all the glycoalkaloids they eat?

This paper took a comprehensive look at potato glycoalkaloids.  Their potential for toxicity was noted.

Also noted was the way these compounds destroyed human cancer cells.

Potatoes produce more glycoalkaloids if they are exposed to the sun.  It turns out people can do a good job of sensing whether a potato should be eaten or not.  Glycoalkaloids produce a bitter taste.  You probably already know not eat a potato if it’s green.

Humans have also accounted for these compounds with technology for a long time.  In the Andes potatoes were essentially freeze-dried for thousands of years, creating a safe, reliable food supply.

Rats eating huge quantities of freeze-dried potatoes showed no ill effects from glycoalkaloids.  However, potatoes did demonstrate anti-tumor properties.  So potatoes have potential hazards but also serious potential benefits.

Potatoes, like other plants we consume, have been selectively bred so their potentially harmful chemicals are in very low concentrations.

Students of evolution should note that Darwin himself was impressed with the potato.  Once again, a food that fueled a population boom can hardly be seen as discordant.  If Cordain is really interested in the way foods have historically affected height, he should love the potato.

The blight leading to the Irish potato famine is an object lessen in crop diversification.  It was so severe only because potatoes had been so dependable and nutritious.

Secondary compounds like glycolalkyloids in plants have long been known to have both useful and potentially harmful properties and have been used accordingly. This excerpt illustrates this well.

As you probably know, antioxidant compounds in plants are believed to have powerful health-promoting properties, including fighting cancer.  But in the real world rather than the oversimplified world of Paleo-logic, even this isn't so straightforward.

Under the right circumstances, antioxidants can actually help cancers develop.

It turns out that not only can antioxidants slow aging and fight disease, but they also can possibly interfere with detoxification or prevent the deaths of cancer cells.  Should antioxidants be demonized the way Paleo demonizes legumes or grains?  Should we say that only lots of meat and animal fat are safe?  Of course not.  As I will show you, the effects of antioxidant-rich plant foods have been overwhelmingly shown to promote human health.

We can fixate on the purported antinutrients in permitted plant foods in the Paleo diet just as they do with grains or legumes.  Here you see Cordain's Paleo cookbook includes recipes for eggplants and raw mushrooms.

All raw mushrooms are known to have some toxicity in humans.  Eggplant also contains the dreaded glycoalkaloids.  Maybe these issues are solved with cooking, but isn't cooking itself evolutionarily novel?

After all, cooking has only occurred in the last two percent of our evolutionary history.  Should there even be such a thing as a Paleo cookbook? And isn’t the eating of toxic substances in plants more in keeping with our most primal history than cooking them away?  Or maybe this whole line of reasoning is just silly.  Plants are highly complex organic substances.  Unless you have a specific disorder, just look at them as whole foods, enjoy them, and leave food toxicology to the food toxicologists.

In the mind of a caveman, if some protein is good then more must be better.  Paleo distorts protein like a funhouse mirror. I’ll try to reflect reality, next.

TPNS 14-16: Define "Healthful"?

Primitive Nutrition 14:
Define "Healthful"?, Part I

Let's turn now from the theoretical justifications of Paleo to its purported health benefits.

Cordain's book contains a section that is de rigueur in diet books.  A contrast is drawn between the proposed diet and the current disastrous eating habits of a lot of us in the United States.  The problem with this comparison is that these awful diets, justified by cost, cravings, and convenience, are not planned for their nutritional benefits, and no one claims they are healthy, although hamburgers might find defenders among the low carbers if the bun is removed.  Yes, Cordain is right that some of us are failing nutritionally.  Practically any reasonable planned diet, and even some unreasonable ones like Paleo, will probably compare well to a junk food diet. Comparing your diet to a diet composed of cheap, fatty, highly marketed industrial foods is just like shooting fish in a barrel.

Cordain shows his lack of confidence in his own diet by choosing to compare it to an imaginary nightmarish incarnation of the junk food diet, which includes a danish for breakfast with coffee and sugar.  To make sure the corn flakes look bad, he adds extra sugar to them, too.  He wants you to remember, as you read about this slow-motion suicide diet, that the USDA wants you to eat lots of grains, implying the danish is what they have in mind.  To be fair to Cordain, other grains consumed in this imaginary day come in the form of a glazed doughnut, a cheese pizza, and yes, a hamburger bun.

Somehow this imaginary worst-case-scenario diet mustered 8 grams of fiber.  I guess this is what it takes to make Paleo look good, in it’s creator’s mind.

Cordain actually asserts, "Many nutritionists would say the example diet is healthful because it contains large amounts of carbohydrates."  Dr Cordain, can you name a single professional nutritionist who would call a diet with only 8 grams of fiber healthful?  With this absurd statement, Cordain demonstrates his total insincerity in matters of public health.

The average American is only consuming 12-18 grams of fiber, so even for the nutritionally oblivious, Cordain's comparison diet is pathetic.

Cordain has his Paleo diet reach 47 grams of fiber, and this indeed is one of its better features.

It is unimpressive, however, compared to examples of past populations.  Here, it is stated that hunter gatherers had diets that were mainly fiber.

This researcher asserts that fiber often exceeded 100 grams per day.

At his Paleobiotics web site, he relates the enormous quantities of fiber that prehistoric peoples have been estimated to have consumed, along with the amazing variety of plants they enjoyed.

Funnily enough, the Paleo diet proposed by Cordain's primitive nutrition partner S Boyd Eaton in 1988 had 150 grams of fiber, well in line with these references.  So why is Cordain so impressed with his 47 grams?

I should mention that there are people out there who say high fiber consumption is harmful.  If you encounter advice along these lines, a little skepticism might be in order.

It seems to me the primitive nutrition promoters engage in some obvious motivated reasoning to justify their beliefs.

Here is a scholarly article Cordain wrote to construct a tenuous argument against grains.  He seems concerned about the ill effects experienced by bakers who inhale flour. What if he applied a similar standard to meat?

A litany of cancers are linked to workers in poultry plants.  Recall that in a previous video I showed you that zoonotic diseases increased with the advent of agriculture as animals were domesticated.  This study demonstrates the cancer-causing effects of zoonotic virus infections, passed from animal to man.

These viruses are likely some of the same that cause butchers' warts.

There is also a paralyzing illness caused by contact with aerosolized pig brains.

Occupational exposure to meat is linked to lung cancer.

When you read Cordain’s concerns about baker’s asthma, you should bear in mind there is a range of illnesses associated with breathing things you shouldn’t breathe.  Flour can contaminate the lungs if you breathe enough of it, just like any other airborne debris.  The serious risks to those who process meats make particles of flour seem rather innocent by comparison, but Cordain doesn’t seem concerned about those.---

Cordain likes to point to a handful of human diet studies that he thinks prove how great Paleo is.  In the next video, I’ll show you those.

They are disappointing, to put it mildly.

Primitive Nutrition 15:
Define "Healthful"?, Part II

Go to the Paleo Diet website and you will see that Loren Cordain references five studies as the primary evidence for the health-promoting power of his diet.

These are the same studies named in this very interesting rebuttal letter written by Cordain to US News, who found the Paleo diet unimpressive in comparison to other diets.

At last place out of 20 diets for weight loss, you can see why this was a disappointment for him.  It was also last place overall.

These are actual quotes from Cordain's rebuttal.

“This comment shows just how uninformed this writer really is.”

“Once again, this statement shows the writer’s ignorance and blatant disregard for the facts.”

“Here is another example of irresponsible and biased journalism, which doesn’t let the facts speak for themselves.”

Cordain's bluster and condescension belie the strength of these studies.  Let's have a look at them so we can decide who is really biased, irresponsible, and uninformed.

Before I begin, I must acknowledge the one big plus for the primitive diet idea.  They advocate the consumption of vegetables, and for some proponents, fruits as well.  This slide is just a token to remind you of the benefits of plant foods. Any favorable outcomes for these Paleo diet studies I attribute at least in part to the plant-based element of the diet.

Here's the first one.  Amazingly, this paper from 1983, two years before the original Boyd Eaton article, is one of the studies Cordain touts as supportive of Paleo.  It is simply a demonstration of the improved health of Aboriginal Australians once reintroduced to their traditional diets, after having eaten a diet that you can be sure was typical of impoverished, lower-status people.  Read a bit of Aboriginal history and you'll see why that is a safe assumption.  Therefore, any whole natural foods of decent quality were likely to be an improvement from their prior foods.  What nutrients made the difference for them?  The paper doesn't say. It does say, however, that they were only consuming 1200 calories per day, which would certainly normalize blood glucose and cholesterol.  It would also guarantee weight loss.  Paleo dieters should note this diet was low fat. Less dietary fat, greater physical activity, and weight loss would have virtually guaranteed improved insulin sensitivity.  This is hardly a compelling argument for Cordain's diet.  Normal factors such as calorie restriction and exercise explain the results here better than any magical effects from the recreation of their Paleolithic milieu.

Here is another Paleo study.  The most serious weakness in this one is the small cohort - only six [***correction: fourteen, not six] subjects for whom they have data.  They started with 20.  It appears six of them dropped out.  Next, we can see this was only a short term intervention.  We don't know how these people would have fared over the long term.  Also, we don't know what the comparison diet was.  These people could have been eating anything before going on Paleo, so a study of this nature can't prove much.  All we know is they consumed 36% fewer calories in these three weeks, which easily accounts for the improvements noted. Antioxidant status improved, no doubt due to the consumption of fruits and vegetables.  Finally, the authors are up front in acknowledging the lack of a control group in this one.  The contents of this article are behind a pay wall, so this is all I have to go by, but it’s still apparent that this one is hardly impressive.

The next study relies on the fish-in-a-barrel technique, as the subjects' terrible normal diets were the basis of comparison.  These diets were not informed by modern nutrition science, as these folks had been consuming nearly 500 milligrams of cholesterol daily.  Thanks to this dismal number, the 311 milligrams consumed on their experimental primitive diet seem pretty reasonable.  This excess of dietary cholesterol, along with the 16 grams of saturated fat they consumed, is hard to avoid with animal protein intake at this level.

311 is still a high number for daily cholesterol intake.  Cordain believes very low blood cholesterol concentrations are right and proper, yet this study which he touts falls far short of conventional recommendations for dietary cholesterol.  It seems inferior by his own standards.

Knowing that success is defined in this study as an improvement on a diet that had almost 500 milligrams of cholesterol and 32 grams of saturated fat, I'm not sure who should be impressed with this one. Notice also the intervention diet only contained 5 fewer grams of carbohydrate.  Therefore, this study hardly tells us anything on that subject.  We aren’t told what the fiber content was in either diet.  All we are told is fiber was increased on the Paleo diet, which was probably very easy to accomplish considering the prior diets of the sedentary, cholesterol-filled individuals used in the study.

The lack of specificity in describing the baseline diet and the lack of a control group render this study useless for drawing important conclusions.  Yes, cut saturated fat and refined carbs and increase fruits and vegetables and you will see better health.  Once again, there is no need for a Paleo idea to explain what happened here.

The title of this one says it all.  This is a victory won on very narrow grounds.  If the world was clamoring for a way to make patients with reduced blood supply to their hearts feel full from a meal sooner, we may have an answer with this one.  Notice that the authors of this study, one of whom is a high-profile Paleo promoter, characterize the so-called Paleolithic diet as low-carb.  Low carb is just plain bad nutrition and I'll show you why later.  Also note that the claimed satiating effects of protein were not observed in this study.  Also notice the pathetic 22 grams of fiber consumed, far below recommended levels.  Their Mediterranean comparison diet was below recommended levels as well.  This matters if you care about satiety.

Some types of dietary fiber have been shown to increase satiety.

Several types of grains have been shown to increase satiety with their fiber intact.  What is often missed in the discussion of whole grains is that dietary fiber seems to have different effects when it is milled into tiny particles, as you find in most whole grain breads.

Also, carbohydrates generally have different effects on satiety depending on whether they are in solid or liquid form, with liquids being less satiating.

Maybe the authors knew this and factored this into the design of their study.  You can see here that the Paleo-style diet benefited from a greater share of whole fruits and vegetables, whereas the Mediterranean diet was loaded with sweet soft drinks, sugary juice, sugary milk, and sauces.  In other words, lots of less-satiating liquid carbs.

As you can see in this graphic from the film, Forks Over Knives, foods of equivalent calories expand the stomach and signal satiety differently depending on their energy density.  Rob carbs of their fiber and they won’t fill you up as much.  Again, we didn't need a Paleo diet idea to tell us what nutrition science already knows.  There was no magic here.

We're back to patients with ischemic heart disease in our last study.  Here they are investigating glucose tolerance.  As you will see in my low carb videos, glucose metabolism is damaged by high-fat diets and is dramatically improved with low fat, whole food, plant-based diets.  Once again, fruits and vegetables probably played a role here.  Let's look at the details.

Here you see changes in body composition between the Paleo diet and what they are calling a consensus Mediterranean-like diet.  It's interesting that the Mediterranean diet did a better job preserving fat-free mass.  Also, notice the relative loss of water weight, common in high protein diets.

Here you see what they ate.  Pretty interesting stuff.  You see the Paleo diet was much lower in calories and saturated fat, which once again is adequate to explain any observed benefits.  Both diets were again high in cholesterol, but it was especially high in the Paleo diet.  Their so-called "consensus" diet was also much higher in glycemic load, and while it was over 70% higher in carbs, it was only 5 grams higher in fiber, telling us they were not particularly healthy carbs.  Still, it bested the Paleo diet's embarrassing 21 grams of fiber.  Yes, refined carbs and sweets are unhealthy.  That's hardly new.  So there was no Paleo solution here, either, folks.  Just one bad diet doing better than another bad diet.  If you are going to eat poorly, eat fewer calories.  That's the message I take away from this one.

Now that you've seen these studies, I ask you, should anyone make a big deal of Paleo based on these results alone?  Do you really think the Paleo diet promoters see in this a Copernican Revolution for nutrition?  Or do you see people with an agenda to peddle a fad diet grasping at any thread of support they can find?

Paleo promoters seem to care about a variety of modern health afflictions.  As we look at a few of them in the next section, perhaps you can see a pattern for what might really help these health challenges.  The pattern is not a primitive diet.

Primitive Nutrition 16:
Define "Healthful"?, Part III

Paleo promoters say their fad diet is good for some specific health issues.  Let's look at a few of them.

They seem to talk a lot about various bowel problems.   If they cared about those problems more than their Paleo agenda, maybe they would draw our attention to some non-Paleo studies.  Here you see that vegetarians have a much lower risk for developing diverticular disease.

Inflammatory bowel diseases are recognized to be genetic disorders yet there are dietary interventions that might combat them that are not Paleo.

Here a patient with Crohn's disease managed to avoid relapse with a semi-vegetarian diet.

Similar benefits with this plant-based approach were later observed in a group of 16 patients over two years.

On the other hand, increased intake of animal protein was the single strongest independent risk factor for Crohn's disease in this study in Japan.

Rural West African children have much healthier intestinal microbes than heavy meat eaters in Italy because of their cereal- and legume-heavy diets.  It seems to me that these healthy foods from the Paleo banned foods list actually improve bowel health.

Paleo promoters also express concern about autoimmune diseases.  Rheumatoid arthritis gets some mentions in The Paleo Diet book, but the findings revealed in this article are ignored.  It seems the iron and fat in meat are not helpful for RA.

Changing to a diet that reduces arachidonic acid might help RA as well.  Meats are high in arachidonic acid.

A vegan diet improves the composition of gut microflora, and consequently the symptoms of RA patients.

As I have shown you, Cordain has chosen to promote his hunter gatherer diet as producing a net base balance, only to have the idea taken seriously by other researchers, who reached a different judgment.  Without entertaining the merits pro or con of the acid diet idea, this was a strange claim for him to make.

Here you can see that generally speaking, animal products are quite acid-producing.  Egg yolks are a big offender.  In comparison, many of Cordain's forbidden foods look pretty good.  With white sugar registering as slightly base-producing, I think we shouldn't invest ourselves too much in this particular issue.

I'll just add here that if you care about acidity, whey protein may not be a good choice.

Vegetarianism would be a great choice, though.  Now that you've seen where meats are on the acidity chart, you know why.

The more plant-based your diet, the less acid your body must eliminate.

Loren Cordain seems interested in cancer and insulin-like growth factor 1.  Large amounts of refined grains are the easy target for him in this excerpt.

Cancer prevention is an interesting place to go for a diet guru promoting the consumption of lots of meat. Normally, in discussions of diet and cancer prevention, fruits and vegetables are seen as a way of neutralizing the risks associated with meats.

Doesn't Cordain know that high protein diets promote IGF-1?

Doesn't he know IGF-1 is lower in vegans?

Maybe that's one reason why highly nutrient-dense vegetarian diets are considered protective against cancer.

And it might be why animal products can be linked to some cancers.

The Paleo Diet is also sold as a solution to general metabolic dysfunction in the forms of metabolic syndrome and diabetes.  But increased conformity to a plant-based diet correlates to better Body Mass Index and lower vulnerability to diabetes.  The 5 unit advantage in BMI for the vegans in this study was called substantial.

This was an eight week trial with great results for diabetics eating high carb, high fiber and plant-based, which meant cereals and legumes in this one.

Studies like that are why the WHO and FAO recommend lots of fruits and vegetables, with carbs as high as 75 percent of calories and protein as low as 10 percent to control chronic disease.

Many of the foods I've mentioned that seem to promote health are on the Paleo banned foods list.  I think Paleo dieters are concerned about these healthy foods because they don't understand plants.  I'll try to set them straight in the next section.

TPNS 13: If You're Serious...

Primitive Nutrition 13:
If You're Serious...

The question must be asked:  Why would you want to base your lifestyle on stone agers?

Those are bugs.  When you see a plate like this, do you salivate?

Well, you should, if you believe your diet is written in your genome.  Insects are eaten by most modern humans today.  Nonhuman primates eat them as well.  Do you really think our evolutionary ancestors in between considered themselves above eating bugs?

The eating of locusts even gets approval in Leviticus.

I have already shown you that Paleolithic humans practiced nutritional cannibalism.  I'll just add here that they ate Neanderthal children as well.

If you're going to be primitive, you'll need some parasites.  I'll borrow a couple slides from this publication now.

We can see in old human waste remnants that stone agers were infested with them.

Parasites accompanied humans as they dispersed from Africa.

Parasites are an important omission with respect to Paleo diet health claims. They have always been with us.  It is well understood these days that our gut bacteria have crucial functions in digestion and immunity, making us not just humans but really superorganisms.  We evolved with parasites as a part of our superorganism, too, and their absence from many of us today is not altogether beneficial.

Parasites were very likely influential in the way our immune system developed.  Does Loren Cordain value his immune system as much as his brain?  He should, and if he's being logically consistent, he should swallow some nematodes with the gusto with which he eats meat, because his immunity would not be what it is today without them.

If you are really doing Paleo and you've taken your parasites to be like Grok, you'll need to start eating some dirt as well.  Being comfortable with parasites means being comfortable eating soil.

Paleo diet promoters are really big on auto-immune and intestinal problems.  It seems for them those issues always relate back to diet.  But have you ever heard a Paleo guru suggest you swallow some worms to calm your bowels?

When you see Loren Cordain's papers referencing the low cholesterol of hunter gatherers, bear in mind these folks almost certainly had parasitic loads.  Parasites are known to affect cholesterol levels.

Here are four references to show you that before we had statins to lower cholesterol, we had parasites.  The cholesterol deniers neglect to mention this, I've noticed.

Here you can see a study of a hunter gatherer community.  Its authors found that they had high parasite loads and high levels of inflammation, but also low blood cholesterol and hardly any atherosclerosis.  Parasites work, but I might prefer to keep my cholesterol in check with a healthy vegan diet.  Paleo-logic may guide you to a parasite-based lipid strategy instead.  Good luck with that.

Of course, don't forget about seasonal nutritional stresses as well.  Put yourself through periods of weight loss and insufficient caloric intake and Grok will tip his hat to you.  Seasonal stress does not mean intermittent fasting, folks.  That's not seasonal.  Also, at the times you are most stressed, avoid eating too much lean meat.

What is the payoff of this lifestyle for the hunter gatherer?  Does he get to enjoy his golden years in good health?  Hardly.  Have a look at these appalling life expectancy figures for Paleo model cultures.  Naturally these figures are skewed by high infant mortality, save for the last line, which is hardly reassuring.

This table makes the outlook clearer.  In the second column you see your expected age of death if you are lucky enough to make it to 15.  With average age of death for this group as low as 51, it becomes clear why no one thought to base a diet book on these people before Loren Cordain.

If you want to romanticize hunter gatherers, you're also going to need to get comfortable with deplorable rates of violent death.  You didn't think primitives avoided disputes through negotiation, trade, and the judiciary, did you?

In the violent days of prehistory, women may have felt a bit less secure than today, too

Of course, no one would choose to revert to a primitive culture.  People do, however, choose a supposedly primitive diet.  They do this because they think it is healthier for them.  Let's see if they are right.  The health claims of Paleo are up next in the Primitive Nutrition series.

TPNS 11-12: Bad Weather, Barren Lands

Primitive Nutrition 11:
Bad Weather, Barren Lands, Part I

Read some Paleo literature and you'll see they are very invested in the belief that the last ice age would have required humans to eat mostly meat.  They think that the climate couldn't have supported carbs.  This is an absurd belief on several levels.

This is a graphical representation of temperatures over the last 100,000 years estimated from ice core measurements.  The far right of the graph takes us to the present day.  You can see why it is believed that prehistoric humans endured much colder climates than today.  Earth's history has been characterized by periodic glacial and interglacial periods.  But notice, the Paleolithic era experienced extreme climate variability.  As this source states, major changes in climate took place within only decades and lasted as briefly as a few centuries.

Computer simulations have been created to clarify regional temperatures during the Last Glacial Maximum.  Here you see results from one of these simulations.  These maps show temperature changes relative to today (the letters MOD here mean the modern climate).  As you can see in the blue and purple areas, some regions were quite significantly colder.  However, other regions, represented in red and orange, were cooler, but not dramatically so.  Of course, we know that a few degrees of change in the Earth's average temperature are very significant, but for our purposes, we are looking for localized areas where climate might have supported vegetation for human food.  I think mean temperatures a few degrees cooler in what are today warm areas hardly creates a situation in which food could only be gotten from hunting big game.

Remember, those were mean temperatures through the whole Last Glacial Maximum. There were also warmer periods during this era.  The periods during which climate is relatively warm during an ice age are call interstadials, and there were many during the Paleolithic.  Here you can see that during one interstadial, summer temperatures could have been warmer than today in some areas.  The region in question here is northern Scandinavia, an area that experienced dramatic cooling during the Last Glacial Maximum.

These scholars are blunt in refuting the perceptions of some about past climates.  Claims that this era was harshly cold are false.

What did our ancestors do during the colder stretches?  They migrated to warmer areas called refugia.  Only during warm periods could they have ventured out of these zones.  Those who didn't migrate to warm areas would have faced extinction.

With this awareness, some scholars have asserted the importance of plants in diets of this time.  In the past, archaeologists have been fixated on meat, as I have shown you already.  Other researchers have resisted this, with one arguing that plants could have composed up to 80% of past diets despite the ice age.

Here, Jonathan Haws succinctly corrects a common fallacy regarding plants in ancient diets.  The absence of evidence does not equal the evidence of absence.

Of course, the Paleo diet is not promoted as an all meat diet.  However, as I will show you in a later video, some use Paleologic to argue for just that.

What about individuals of European descent? Are their genes so different, as some claim?  Do they so clearly manifest a cold-conditioned genetic legacy?  Not necessarily.  The genetic evidence indicates that those with the oldest European ancestry found Eastern Europe too cold and inhospitable to inhabit at the time.  Instead, they migrated to refuges as well, where they intermingled their genes with those of people from more temperate regions.

Here is an example of how gene flow during the Paleolithic affected our present day genetic makeup.  West Eurasian, Jewish and some Middle Eastern populations have African genes dating to the Paleolithic.  Very few of us have a genetic legacy so clearly conditioned by a cold climate.

I think this abstract is enlightening.  It has become clear that there were refuge areas in northern latitudes that could have harbored a variety of plants as well.  The Pleistocene epoch referenced here includes the Paleolithic, and it is clear that this era was highly dynamic.

It could be argued that the environmental stresses of the ice age actually drove humans  toward agriculture, as plants offered a more reliable source of nutrition, or as The Economist put it, it turned people much more vegetarian.

Taken together, observations from this period weigh against the meat-based Paleo diet concept, I believe.  The broad scope of 85 million years of evolutionary history seems built on plants.  For that to have been undone during the Paleolithic, selection pressures would have had to have been strong and consistent.  Instead, the variability of climate along with migratory patterns mitigating the harshest climate stresses would have conditioned our ancestors mostly to simply be adaptable.  As stated earlier, adaptations are not lost unless they become disadvantageous.  Clearly, a capacity to find nutriment from a variety of sources would have benefited a generalist species like us.

As we have seen, humans have migrated and followed predictable patterns of dispersal like any other species.  This brings me to one of the more peculiar leaps of Paleo-logic - the idea that hunter gatherer populations are appropriate models of diet and health for the rest of us.  I start with this slide to establish a principle.  Populations tend to expand as far as they can.  Reproduction and competition drive this, and humans have been particularly successful in establishing new territories in a variety of conditions.

Sometimes these attempts at colonization fail.  We think of circumpolar cultures as masters of survival, fully leveraging any lifeline in their environment.  They have to be.  We don't see the people who failed to find a way to survive. They're long dead.

It is common sense that such populations could not have had much influence on our genes. They were isolated from the populations that were left to generate our genetic diversity.

When migrants move into marginal new territories and manage to establish a stable population, they can become isolated from their source populations.  The collective genetic material of the remote population is no longer influenced by the source population.  They are under unique stresses from their marginal environment that affect what traits are selected for inheritance.  It is also under these circumstances that genetic drift becomes a key factor in establishing new mutations.  This is the same principal as inbreeding.  A lack of genetic diversity promotes non-adaptive mutations.

So when Mark Sisson says that in our ever more globalized world there has been more cultural inbreeding and genetic drift, he has it exactly wrong.  Where genetic drift is a major factor is in isolated hunter gatherer populations that are the model for the primitive diet philosophy.

Let's look at Sewell Wright's adaptive landscape to visualize genetic drift.  The arrow all the way to the left shows the expected direction of selection in favor of fitness.  Genetic drift does not move like this.  Rather than moving vertically toward a peak in the landscape, genetic drift can be imagined to move horizontally, simply meandering around the landscape without really moving toward greater fitness.

Genetic drift was a factor for all of us, but in Paleo days.  Before the out-of-Africa expansion across the world most of the genetic diversity in humans was generated in Africa.  Genetic drift came to be a bigger factor during the Paleolithic when genetic diversity was reduced.

Studies of human DNA are suggestive of a major bottleneck during the Upper Paleolithic, in which the total human population appears to have been sharply reduced.  Some believe this was due to a massive volcanic eruption that may have driven our ancestors close to extinction.

Whether it was this event or something else that accounts for the appearance of a genetic bottleneck is debated.

In any case, movements of populations out of Africa seem to have been accompanied by a reduction in genetic diversity.  In more marginal environments, humans would have had fewer food resources.  After all, if the environment necessitated hunting reindeer, for example, variations in the number of reindeer would have threatened these populations.  It is under these circumstances, the romanticized Paleo genome conditioning era, that more genetic drift, or more inbreeding, was introduced into the genome.  As we have seen, the past ice age did not subject humans to strong and consistent enough selective pressure to undo our African, unclothed legacy.  Here we see that efforts to migrate into Europe made genetic drift a greater force.

This seems to have had interesting implications for disease vulnerability.  Prostate cancer is over-represented in Northern Europeans.  We see that with admixture, or the mixing of genetic material between populations, disease rates change.  Native Africans are unlikely to develop prostate cancer.  African Americans, whose genes are usually not exclusively African, are more vulnerable.

European admixture also appears to make African descendants more vulnerable to atrial fibrillation.

The same can be said for rheumatoid arthritis.

The stresses on populations in the Paleolithic have left a striking result in our genes today.  Amazingly, there is more variation within populations than there is between populations.    Once again, we have evidence that at root, what we have most in common is the part of us that is an African from a warm climate.

Further evidence of the importance of our African roots is our tendency toward high blood pressure.

This is because salt retention is adaptive in hot, humid climates with a low availability of dietary salt.  The fact that we retain this tendency today argues against our basic nature being best suited to cold climates.

In part two of this video, I'll show you how these issues have lead to one of the biggest flaws in Paleo-logic.

Primitive Nutrition 12:
Bad Weather, Barren Lands, Part II

The first part of this section, in which I looked at the last ice age and genetic drift, just sets us up for an even bigger goof in Paleo-logic.

Loren Cordain acknowledges it is difficult to say what prehistoric populations ate.  So far, so good.  That should be enough to undermine his idea for a historic meat-based diet, or at least it should cause him to add a few qualifiers when laying out his one and only ideal human diet.  But then he makes a huge mistake.  He assumes that somehow hunter gatherers are good representatives for all the rest of us.  Their dietary practices, regardless of plant to animal ratios, are so diverse it would seem one would not even be tempted to force them into a single template.  But that's exactly what Paleologic does.  They are all essentially the same as each other, and we are essentially the same as them.

Here you can see that as of December 2010 Loren Cordain was still publishing papers built on this premise, which as you see is itself built on the faulty premise of stagnant evolution.

We can undermine this logic very easily if we look at the big picture.  Here you see the locations of the cradles of civilization that took root with the beginnings of agriculture.

Here is a similar map showing where agriculture developed first in orange.  If you are watching this, chances are you have a genetic legacy originating from one of these places.

Now look where hunter gatherer populations were in 1950.  They are not in areas that supported agriculture and this is not a coincidence.  They expanded into marginal lands, and as a consequence, they have remained frozen in time.  Paleo-logic essentially acknowledges these people were left in the stone age.  Should it be a surprise that they rely on animal foods in marginal lands?  Of course not.  These places are considered marginal because they have fewer food resources.  Look how scattered across the globe they are.  They all represent little isolated pockets of genetic drift.  To trace back a point in history when they were all together, along with all other human lineages, you’d have to go back to our origins in Africa, the birthplace of the naked ape.

Here is another map of hunter gatherers compiled by Frank Marlowe.  This is a wonderful paper.

Primitive populations heavily rely on animals foods simply because animals provide them the only way to extract enough calories from their marginal lands.

This is not lost on Marlowe.  He considers them a biased sample, and one that doesn't represent pre-agricultural societies.

Here you see what should be one of the more obvious trends embedded in the hunter gatherer food patterns.  As populations move to more extreme latitudes lacking in vegetation, they are forced to gather less and hunt and fish more.

Marlowe offers a further insight into diet and lifestyle for hunter gatherers here.  This pertains to the need for camp relocations to be near food.  You can see that the more  hunting is done, the more movement is necessary.  I suspect cultures and economies would be less able to develop in nomadic populations.  Fishing is more like plant foods in this regard as it seems to promote sedentism, which is not surprising.

Optimal foraging theory states that hunter gatherers will direct their time and effort to maximize food acquisition.  This drives populations toward hunting if calories cannot be obtained in an easier way from plants.  It also surely dictates the need to move frequently for nomadic hunters.

Knowing now that hunter gatherers are characterized by relative isolation and marginal ecological niches, it should not be surprising that to the degree our genes do differ, they tend to set us apart from these cultures. FIX

Anyone trying to make an argument for starches not being in compliance with the genome would need to explain why we have adaptations that favor the digestion of starch.

Here you see copy number variations in the human genome for genes related to starch digestion.  Notice that groups with lower copy numbers for a starch-related gene are hunter gatherers, while European Americans tend to have more.

In contrast, cold weather populations  demonstrate a deficiency in enzymes for digesting carbohydrate.

There are many examples of unique polymorphisms in hunter gatherer populations.  Here you see that Inuits, who I will discuss at length in another section, have one that raises their cholesterol.

In spite of their elevated cholesterol, Inuit may have a loss of a functional mutation related to fat metabolism that protects them from heart disease.

This study also finds polymorphisms among the Inuit that are associated with heart disease.  These may be signs of genetic drift.

Inuit have been shown to have a high resting metabolic rate.  An adaptation like this makes sense for people inhabiting cold climates.

But this is an adaptation you may not want.

Unlike the Inuit, here is a cold weather hunter gatherer population that has a mutation that lowers their cholesterol.

Loren Cordain seems unaware of the importance of the genetic differences in isolated populations.  Here he mentions the example of the Ache as supportive of very high protein diets.  The Ache are some of the least genetically diverse people in the world.

Perhaps along with their high meat consumption he could point out their low testosterone levels.

The example above them doesn't raise confidence in Cordain's conclusions, either.  Spelling "Arnhem Land" wrong is a bad sign from Dr Cordain.

The natives of Arnhem Land have been genetically isolated for almost 20,000 years.

Australian aboriginals themselves are an isolated population, and are therefore more subject to genetic drift.

And the natives of Arnhem Land are among the most genetically differentiated of Aboriginals.

The Paleo crowd is so fixated on primitives, I wonder why they won't go all the way in copying their lifestyles.  In the next video, I'll show them how to do that if they want to try real Paleo.

TPNS 9-10: Primal Primates

Primitive Nutrition 9:
Primal Primates, Part I

Paleo promoters say that both the archaeological record and our genes point indisputably to their faddish meaty diet.  I'm going to make a counterargument to that, but before I do, I want to make absolutely clear I do not think history should trump nutrition science.  If we approach nutrition just through history we are falling for the appeal to nature and the appeal to tradition fallacies.  There is more than enough good nutrition science that tells us about the effects of different foods on human health.  It seems to me it is impractical if not impossible to recreate past diets, even if we could figure out what they were.

Which diet would we pick?  What region?  What time period?  Would our plant foods be just like theirs or would we be forced to use modern varieties?  And would we strictly forbid anything that wouldn't have been found in that time and place?  And how would we pick that particular time and place?  Was that moment the pinnacle of human evolution?  I could go on but I'll stop there.

I think a narrowly historical approach to food is absurd.  I am engaging this topic only because it is apparently important to some people. To me this reasoning is just myth making and nostalgia. I have no qualms about looking at diet from a purely modern, purely nutritional perspective. Now that that's off my chest, here goes nothing!

Paleo advocates say archaeologists find evidence of meat eating in all ancient human cultures studied so far, as in this article.  Therefore, we are meat eaters who should eat meat.  Case closed.

But how much meat?  And what about our pre-human ancestors?  Cordain doesn't want to get into that history.

Here is an interesting excerpt from Mark Sisson's The Primal Blueprint that ties in to this issue.  This might be a good one to pause and read.   He is amazing when it comes to sheer density of misinformation.  I'll try to correct some of this.

First, as I've shown you, human evolution has likely accelerated more recently.

The distinction he tries to make about how evolution is different now is nonsense.  If a trait is being consistently favored in a population, that is an adaptation through natural selection, period.  It's not genetic drift.

Genetic drift is not a helpful concept for the Paleo view.  It's a bigger factor in small populations, not large ones, so he apparently doesn't understand the term.  I'll talk about genetic drift later when I look at hunter gatherers.

Look at that bottom sentence.  He is stepping in the teleological fallacy by saying that evolution is somehow directed toward something better.  I covered this already.  No one who understands evolution would write such a thing.

But I want to focus on one sentence, right in the middle of the slide. He mentions the basic ways we metabolize food, saying it hasn't changed since prehistory.  When does he think our digestive organs first developed?  When we learned to make a hand ax?  Why do all other animals have essentially the same organs as us?  Does he think we changed all that much when we split off from other primates?

This Paleo-logic has interesting implications.  It's as though we have nothing in common with our closest animal relatives.  I find it ironic that the world's most enthusiastic consumers of animals are unwittingly arguing against the scientific value of animal experimentation, as if our digestive organs are totally different from those in chimps.

The Paleo folks should explain their beliefs to the researchers who experiment on animals.  Here a German ethics advisory group says animal experimentation has a high predictive value of effects in humans. If we are so different in our basic metabolism, how would that be possible?

The California Biomedical Research Association seems to think primates are an irreplaceable model for the study of heart disease and cancer.  Both of these conditions are influenced by diet.

Apparently a high fat, high cholesterol diet - the kind of diet Sisson thinks is good - gives rhesus monkeys atherosclerosis.  Does he think research like this was done to figure out how best to feed monkeys?  Now you know not to feed your monkey a cheeseburger.

Animals have been experimented upon through the whole history of medical research because of our deep similarities to them.  If a high-cholesterol diet does this to a monkey, it might do the same to us.

If you think humans aren't closely related to primates and other animals, here's something to ponder.

This is a human baby born with a tail.  Similar events have been reported occasionally in the medical literature.

Here is an abstract dealing with three such cases.  Actually, we all have a vestigial tail, although it's not as well-developed as these.  We call it our tailbone or coccyx.  What do these amazing cases demonstrate?

Once again, Gary Marcus has it right.  Evolution does not have the option of doing complete redesigns.  Evolution can only build on previous genetic inheritance. Our tailbones prove our ancestors had tails.

Here you see some examples of a concept called homology.  You can see that even though all the species pictured are very different, they inherited similar body plans and differentiated from there.  Internal organs are also homologous,

which is why biology classes have historically performed dissections, and it's why pre-med students take mammalian physiology.  The changes from one form to another represent adaptations through natural selection.  The basic body plan doesn't change much, though.  It can't because evolution is about small changes over time.

Even if past adaptations are not particularly useful later, they are retained if they are not disadvantageous.  This means every organism is a compromise, or a kluge.  An adaptation only has to be good enough.

Past adaptations that developed our livers, for, example, have not needed to change much.  The liver's basic functions go way back, far enough that it works much the same as the liver in a mouse.

Recently a phylogenetic tree was created to represent all living primates.  I think it helps put us in some evolutionary context.  The genus homo  split off around 2.3 million years ago, but the order of primates goes back 85 million years.

Compare that to the usual date range for Paleo of 10,000 to 2.5 million years.

Here you see the phylogenetic tree created by these researchers.  I have circled our position in the tree.

Zoom in and you can see us, homo sapiens.  All the primate species nearest us - chimps, orangutans, and bonobos - eat plant-dominated diets.

Our closest primate relative is the chimpanzee.  You can see here that chimpanzees eat a highly varied plant-based diet that relies heavily on fruit.  Our evolutionary path split from that of chimps between five and seven million years ago.

Fast forward in evolutionary history to the hominid Australopith genus, which were almost certainly direct ancestors to all homo species.

The Australopiths were not pre-adapted to eating meat.

You can see where the important hominid finds were made, including Australopiths.  There can be little doubt we originated and spent most of our evolutionary history in Africa.

Before their migration from Africa our ancestors, were able to survive without either clothing or body hair, which should tell us something about the warm temperatures they experienced.  This date takes us through the development of anatomically modern humans.  Think of what that means for food.  Remember this when low carbers suggest you should eat like an Eskimo.

When it comes to nutrition, we are fundamentally African.

Reading the literature on early humans, it is clear to me that we need to be comfortable with a certain level of uncertainty.  There is some debate, for example, about how humans got to Eurasia.

You can imagine what a challenge it must be to piece together human migrations going back 75,000 years.  It seems this history isn't established well enough to support a fallacious appeal to nature, if you really want to go that route.

Neanderthals provide a good example of our hazy view of past diets.

As you may know, they have mostly been depicted as top level carnivores.  However, it is now clear that they ate plant foods.  It is quite interesting, I think, that even these extreme meat eaters have been shown to have eaten legumes and grains.  Maybe Loren Cordain thinks they went extinct from eating too many lectins.

Samples demonstrating these foods in their diets are around 35,000 years old.

These researchers find little support for a believe that our ancestors relied on specific foods, contrary to Paleo beliefs.  The adaptation was not to meat, but to ever greater variety, and I think that is the bottom line.  We succeeded because we are adaptable.

They lay out some of the difficulties with trying to reconstruct past diets.  Small sample size is most problematic, but they all obscure our view of the past.

These and other issues may have lead to a systematic underestimation of the use of plant foods, as I'll show you in part II.

Primitive Nutrition 10:
Primal Primates, Part II

In part one of Primal Primates, I explained that it is too difficult to piece together past diets to be confident we know the truth about what ancient humans really ate.  Plant foods are especially hard to account for in archaeology.

Unfortunately, one of the reasons plant remains have not been mentioned in fossil studies much is because researchers have not always tried to find them.

It seems strange to assume that plant foods were not exploited extensively throughout the history of homo.  The processing of plant foods has been observed in chimpanzees and in modern hunter gatherers.  Why should this not have been the case for all the stages of evolution in between?

Plant foods that were likely important components of past diets were not preserved in the fossil record because they decompose so easily.

This has lead to what is probably an overemphasis on meat-eating by our ancestors.   The more contemporary researchers look for evidence of plant-eating, the more they find it.

This scientist believed evidence of carnivory may tell us little about the overall importance of meat in past diets.  He thought there was some bias in past interpretations of diet toward meat-eating.  I'll add that endeavoring to concoct a fad diet out of fossils introduces the possibility of bias as well.

Loren Cordain personifies that bias.  Here he makes the familiar argument that meat allowed for our big brains, or our high degree of what is called encephalization.  He says he wouldn't be a scientist if humans hadn't eaten meat.    He is therefore a scientist who is apparently completely comfortable with the appeal to nature fallacy.  Maybe my brain isn't as big as his, but this raises some questions for me, the first being, so what?  Why does this mean we should eat meat now?  Is our environment the same as theirs was?  Did early humans have  easy access to high quality grocery stores with a diverse year-round selection of beautiful produce?  Does he think he is growing his brain if he eats a steak today?  And is the science really so clear that it was the meat and not the practice of cooking that fueled the growth of our brains?

It is not at all clear that it was meat consumption that lead to our split from other primates.

These researchers find homo encephalization to be better explained by the consumption of underground storage organs like potatoes.

They say it is not clear how much meat the homo genus ate and why.

Here you can see a recent assessment of the vegetation that existed through the last six million years or so.  One of the authors accepts the idea that meat was important for encephalization.  However, his quote at the bottom is representative of a disinterested scientist, as opposed to someone with a diet book agenda.  He says,

"Anybody who isn't confused doesn't know what's going on."

That's a real contrast to absolutist Paleo rhetoric.

Cordain also fails to consider the role culture might have played in the development of bigger brains.

The best thinking I've read on the effects of hominid diets on brain size has come from Richard Wrangham of Harvard's Department of Human Evolutionary Biology.  In this article, he and Rachel Carmody make a powerful case that the uniquely human practice of the cooking of food would have provided the necessary energy to grow our big brains.  This section on raw diets is especially interesting.  Raw dieters tend to have relatively low body mass.  Raw foods, whether meat or plant, could not have provided the surplus of energy needed for encephalization.

Let's think about encephalization another way.  Here Loren Cordain says lean meat is brain food, without which we would have brains like chimps.

The argument he puts forth is that eating meat gave our ancestors more food energy.  He says energy because he doesn't want to say calories.  If he did say calories, the flaws in his Paleo-logic would be plain.  So meat gives you more calories.  Is that why people buy diet books, to find out how to eat more calories?  And if excess calories are what made big brains possible, why would lean meats be the choice over fatty meats?  After all, protein and carbs are both 4 calories per gram and fat is 9 calories per gram.

Actually, if you accept other Paleo talking points, lean meat would give you less net energy than carbs because it is thermally inefficient and because it ruins your appetite.  It seems to me Cordain isn't being logically consistent.

Maybe this dilemma with calories is why he adds DHA to the argument.  He doesn't develop the thought, but instead, in the same paragraph, he says early humans in England were top level carnivores like wolves.  This was 12,000 years ago.  Isn't that too recent for adaptations to food according to him?  And what about humans everywhere else?  And how healthy were these people in England?  And is he saying the Paleo Diet concept tells us we should eat like wolves? Why then doesn't his diet look like a wolf diet?  I guess you need to be a primitive to understand him.

All this should give pause to anyone trying to justify their diet strategy through runaway speculation about evolution.  It's far too easy to concoct a just-so story to justify the ideas for a fad diet book.  I’ll concede there is one way meat eating may have caused brains to grow a little bit.  It must take a lot of grey matter to make up so many excuses to eat meat, while avoiding all the obvious reasons we should not.

One part of the fallacy-ridden argument for meat eating is the claim that the last ice age would have required our ancestors to follow a carnivorous diet.  This very weak line of argumentation is addressed next.