Monthly Archives: March 2013

Happy Easter!

Spring is here. From our walk today, nesting ducks:

And a muskrat:

Around the Web: Palm Sunday Edition

The Audible edition of our book will be released tomorrow, Monday, March 25. Also, early buyers of our Kindle edition received email notice from Amazon last week of a major update: this fixes the links to notes.

This week I’ll be at PaleoFX and posting will be light. There are still a few tickets available, so if you can make it to Austin, please do!

Also, the 2013 Ancestral Health Symposium is accepting registrations. Only a limited number of rooms at the Sheraton are available at the event rate, so please consider making plans now.

[1] Music to read by: I feel a sermon coming on …

We try to follow Johnny Mercer’s prescription. The attitude of doing right is:

  • Look for goodness in others and encourage it; overlook faults.
  • Ac-cent-tchu-ate the positive, eliminate the negative.

Robert Louis Stevenson, too, had a good attitude:

  • “There is no duty we so much underrate as the duty of being happy. By being happy we sow anonymous benefits upon the world.”
  • “Our business in life is not to succeed, but to continue to fail in good spirits.”

So let us be happy, and seek good health in good spirits!

[2] Reader results: There is much to celebrate.

Hillary reports that PHD has been life-changing:

Life changing in that it’s the first “diet” I can see being a long term lifestyle, I’ve already lost ten pounds without trying and for once I’m eating healthy because I want to be healthy, not because I want to lose weight (although that’s been a great benefit). It’s much easier to stick with something because it makes your body feel good, not for the fad of it. I’ve got my husband on it as well. We’re eating things we never thought about making before – I’ve recently made goat and oxtail stews, which was a first. I don’t crave sugar anymore, which is amazing and I love that I can still eat chocolate daily (I have a square of 90% topped with a date to sweeten it up) and a glass of wine.

Elizabeth Perez had an epiphany:

I can still remember that first night I had a PHD homecooked meal. I had been fat phobic and eating brown rice and whole wheat bread and the very first time I heard Dr Mercola and Jaminet talk I got some fatty beef with carrots celery and onions in my crockpot and 8 hours later around 11pm had my first home made stew with white rice and avocado and I felt this indescribable nourishing just ‘right’ feeling in my gut and body and that night I slept like a baby. That interview just made so much common sense and left me with this gut feeling like ‘I just knew’ it was true and got ‘permission’ to enjoy a fatty meal. Something in me ‘remembered’ all Jaminet was saying. Weird right? But anyway it was the interview and meal that changed my life forever. Lol.

Claire reports a cure of her IBS:

Hi Paul!

I recently started taking N-acetylcysteine after reading your blog posts about IBS and bowel disease. For the past two years I’ve been in pain, had irregular bowel movements, basically everything that goes with IBS. However, after starting NAC, I HAVE NO MORE IBS AT ALL!!!!!!!!!!!!!!


I’m stunned. I was hoping to understand why on earth this has helped so greatly? I don’t understand what it “fixed?”

The PHD book and this blog have literally saved my health and my sanity. I am eternally grateful.

Libba writes:

I have been faithfully sticking to PHD for one month and have seen drastic improvement! I am so grateful to you and your wife for the work and knowledge you have shared. I have 40 stubborn pounds to lose, scalp psoriasis, acne and other random ailments. I’m down 9 lbs, have more energy than I can remember and my scalp and skin have never looked better (if I do say so myself)!

Long-time commenter Mari writes:

Thank you, Paul, for PHD.

When I first started following the PHD diet and lifestyle recommendations two years ago, I wrote up a list of the various issues that were bothering me: frequent blackouts, cold extremities, digestive issues, hair loss, chronic sinus infections, extremely low blood pressure, low blood sugar, no sensation of hunger, migraines, muscle weakness, insomnia, etc. Without having to think too hard, I came up with 37 health issues.

On my one year anniversary of adopting PHD, I went over my list and saw that nearly all of those issues were gone. There were some new things that that I became aware of as I worked on tweaking to find what worked best for my body. Still, I had only 2 of my initial health symptoms, and a few new ones.

Now, on my second year anniversary of PHD, I have none(!) of the initial health issues. I have a few things that are new since starting PHD–such as a lot more build-up on my teeth–but I can say that following the PHD template has completely changed my health, energy, and mood. And I’m sure by year three, with some tweaking, these last few things will be scratched off the list.

Carmelite wrote:

I just started your diet last week, have not even completely implemented it yet, and am already seeing amazing benefits to my mood, energy levels, and a reduction in food cravings.

A Chinese emailer wrote:

I find that the PHD diet has worked really well. You are so right; when the nutrients are at an optimal level for peak health, I feel very well, physically and emotionally. I neither overeat nor undereat and just feel like a well oiled machine with lots of energy and my mood is on an even keel.

We’re very interested in pregnancy and nursing anecdotes. Meg reports that PHD is great for generating breast milk:

I have had amazing success on your diet after struggling for years to balance my motherly demands and lose weight. I have been breastfeeding and/or pregnant for almost 6 years, and I found that when following low-fat or low-carb diets while breastfeeding, milk supply will diminish. For years I tried cutting calories, cutting carbs, cutting fat, etc, always with the same result= no milk and a mad baby. I started PHD in December and have lost 15 pounds so far (about 10-15 more to go), I feel great, and I have TONS of milk. And the milk has changed! I can tell because the babies (ages 2 and 10 mos) don’t seem to need to nurse as often, and their bowel movements are much healthier looking. Sorry for TMI, but I know that sharing my experience will help someone else eventually.

Daniel Kitching writes:

I have been on the PHD for nearly three weeks now, and I’m seeing AMAZING results. I feel great, I’m not hungry or craving, and I’m discovering new, delicious foods. I even was able to stick to it while at Walt Disney World. Thanks A MILLION!

Laurie has done better on PHD than on low-carb or high-carb:

I’ve only been following the PHD for a less than a week, so I’m still trying to figure out just what works for me. First thing I can say is that I have never felt quite so satisfied and full on any diet as this one. Going 16 hours without eating (except for coffee and cream/coconut oil in the morning) has been an absolute breeze.

I feel full and satisfied after each meal, and that feeling sticks around for a long long time! I thought carbs made me hungry. Turns out it was wheat that gave me the cravings. I’m fine with potatoes and rice! Better than fine, really! I’m amazed at how great I feel!

I’m a person who has always struggled with hunger. I’m just not good at white knuckling through it! I thought I had hit the jackpot when I found low carb. Eating low carb was the closest I had ever come to actually controlling my appetite. Sadly, I didn’t keep it up forever, and gained all my weight back, plus some.

So did Caressa Santella Neary:

Dear Paul and Shou-Ching, I just had to tell you both how much I love the new edition of your book! I have been on a low carb and high fat diet for many years and my weight loss had stalled and my energy levels were terrible. I added some safe starches and cut back on added fat on my foods and am happy to report your approach has restarted my weight loss and improved my energy levels and mood, very excited!

Lynh writes:

My things which resolved:

1) No more cold/canker sores.

2) more energy! and a better mood.

3) I feel satiated with the rice, potatoes, or sweet potatoes

4) finally – a more normal body temperature! this has been the best part, I used to feel cold all the time and supplementing with iodine and selenium, diet, etc., my body temperature went from 97 to 98.2. I don’t need a coat anymore when it’s cold outside and I used to be freezing all the time.

I really like the explanations for everything in this book, I wish it were required reading for medical school students.

Tim Freeman tweeted:

Dropped 20 pounds in 28 days with PHD. No hunger, better mood, and better sleep.

David wrote:

Oh yes, things have definitely gotten better with PHD. I came from a gluten-free standard american diet (GFSAD ), eating out 3 times a day. I was already off gluten for two and a half years before PHD, but transitioned quickly and almost live in the kitchen now. I’ve lost over 40 pounds since starting PHD and have maintained it easily for quite a while now. Thank you guys so much for your work. Glad I found it first before going on to read books on Paleo and Primal. I’m just about finished with the 2nd edition of PHD, awesome work.

Our thanks to everyone who shares their results or writes Amazon reviews! We’re most grateful.

[3] Cute animals:

Via Yves Smith.

Bonus: A new breed of chauffeur:

[4] Interesting items:

The English of the mid-1800s had a life expectancy at age 5 similar to ours, despite a far higher incidence of infectious disease; credit belongs to their healthy diets and lifestyles. This finding is more evidence that diet and lifestyle can substantially reduce risk of cardiovascular disease and cancer.

Miki Ben-Dor reviewed Marlene Zuk’s Paleofantasy and Christina Warinner’s TEDx talk that I mentioned positively last week. He thinks her anthropology is wrong, and suspects her of anti-meatism.

Sally Fallon critiques Paleo.

Neely Quinn points out that if you’re craving carbs, you just might need carbs. Women’s Health Mag has further tips on what food cravings may mean (via Craig Newmark).

Seth Roberts believes in earwax transplants for ear infections.

The Atlantic looks into why published research misleads us.

Emily Deans reports that early-life malnourishment affects adult personality traits.

Via Connie Warner, “Let them eat fat.”

Another reason to avoid multivitamins: Via ProfDrAndro, manganese increases the virulence of the Lyme disease pathogen Borrelia and presumably other pathogens too.

Keeping track of Paleo parodists: Hunter Gavera, who authored this Paleo manifesto, might be the same person as MatthewGreenUK who assembled this video and as Walter West, Paleo Caveman. He might be a different person than Paleo Dooche,.  Via Meredith Harbour Yetter.

The dose makes the poison.

Sarah the Healthy Home Economist shows that food reward really does promote acquisition of the healthiest foods – even in thieves!

Maybe a rice diet isn’t so great for chickens.

[5] Never lose hope: I didn’t know this: In his 30s, Alexander Solzhenitsyn was diagnosed with a late-stage malignant cancer and was not expected to live, but after converting to Christianity staged a recovery he regarded as miraculous.

He went on to win the Nobel Prize for Literature and to chronicle the evil of Soviet prison camps. One of his best passages:

If only there were evil people somewhere insidiously committing evil deeds, and it were necessary only to separate them from the rest of us and destroy them. But the line dividing good and evil cuts through the heart of every human being. And who is willing to destroy a piece of his own heart?

[6] Not the weekly video: What an inspiration!

[7] Shou-Ching’s Photo Art:

[8] Weekly Video:

Will Harris is a zero-waste farmer, is pioneering zero-waste natural cattle raising at White Oak Pastures. Watch this terrific video (via PrimalDocs):

Shou-Ching’s Mom’s Kimchi

We previously offered a recipe for Homemade Kimchi (June 26, 2011). It is an excellent recipe, but Shou-Ching wanted to continue experimenting until she reproduced the flavor and texture of her mother’s kimchi that she loved as a child growing up in Korea.

She thinks she’s got it.

Health Benefits of Kimchi

But before we share the recipe, a few reasons to make kimchi. Kimchi has been reported to:

  • Reduce body weight and blood pressure in the overweight and obese. [1]
  • Inhibit autoimmune diseases such as atopic dermatitis [2]
  • Inhibit development of allergy. [3]
  • Have anticancer effects. [4]
  • Inhibit development of atherosclerosis. [5]
  • Have antimicrobial effects on some of the most common gut pathogens, including Listeria, Staphylococcus, Salmonella, Vibrio, and Enterobacter. [6]

Against those benefits, kimchi consumption has been associated with higher rates of stomach cancer [7], perhaps due to its high content of salt [8] or N-nitroso compounds [9].

Homemade kimchi is far superior to store-bought kimchi. To accelerate fermentation, commercial kimchis usually contain sugar, but this means they will go bad soon after exposure to oxygen. Homemade kimchi, without added sugar, can retain its freshness up to several weeks after it is first exposed to air. The mix of bacteria in homemade kimchi may be far more healthful.

Preparing the Kimchi

This version starts with one large head of Chinese or Napa cabbage and the following vegetables:

  • A daikon radish
  • An equal volume of carrots
  • Green onion
  • Garlic
  • Ginger

Set aside the cabbage for a bit. Shred the radish and carrots in a grater; mince the green onion, garlic, and ginger in a food processor. Add 3 tbsp chili powder:

Mix the vegetables thoroughly and add salt and fish sauce (optional, but we use 1 tbsp of a light fish sauce) to taste:

Cover these vegetables in plastic wrap, to start the fermentation off in the right direction, for a few hours while preparing the cabbage.

Cut the head of cabbage lengthwise in half, and then each half in quarters, all lengthwise:

Then chop along the other direction until the whole cabbage is reduced to bite size pieces.

Transfer the chopped cabbage to a bowl a handful at a time – a handful of cabbage, a teaspoon of salt; a handful of cabbage, a teaspoon of salt; continue transferring cabbage and salt until all the cabbage is in the bowl:

Put a weight on top of the cabbage to compress it and release water:

Wait two hours. Over this time the cabbage will shrink as it loses water:

After two hours, rinse the cabbage in fresh water and put it in a strainer. Take the cabbage in your hands and squeeze water out; then transfer the dehydrated cabbage to the other bowl with the mixed vegetables. Continue until all the cabbage has been transferred.

Mix the cabbage and the other vegetables thoroughly:

Taste the mixture to see if it needs more salt. Transfer everything to a container that can make an airtight seal for the fermentation process.

It is important to create an anaerobic environment, similar to that in the gut. This pyrex bowl with a plastic lid makes an airtight seal:

In case pressure should build up and break the seal, we enclosed the container in a plastic bag:

Leave the sealed container at room temperature in a dark place for four to seven days before opening. It should have a mildly sour (acidic) taste; that signifies the presence of lactic acid from lactic acid generating bacteria.



Depending on how much water was squeezed out of the cabbage, the kimchi may be more or less watery. There’s nothing wrong with a watery ferment, but when more water is present, more salt may be needed to achieve an appropriately acidic ferment.

As time goes on, the kimchi will become increasingly sour. When the taste starts to become unpleasant, Koreans cook the kimchi into a soup, killing the bacteria. Some of the benefits of kimchi are retained if the kimchi is cooked. [3]

Although with live cultures anything is possible and a few people may experience digestive disturbances from eating kimchi, many more find that kimchi improves their digestive function. It is an excellent probiotic.


[1] Kim EK et al. Fermented kimchi reduces body weight and improves metabolic parameters in overweight and obese patients. Nutr Res. 2011 Jun;31(6):436-43.

[2] Won TJ et al. Therapeutic potential of Lactobacillus plantarum CJLP133 for house-dust mite-induced dermatitis in NC/Nga mice. Cell Immunol. 2012 May-Jun;277(1-2):49-57. Won TJ et al. Oral administration of Lactobacillus strains from Kimchi inhibits atopic dermatitis in NC/Nga mice. J Appl Microbiol. 2011 May;110(5):1195-202.

[3] Hong HJ et al. Differential suppression of heat-killed lactobacilli isolated from kimchi, a Korean traditional food, on airway hyper-responsiveness in mice. J Clin Immunol. 2010 May;30(3):449-58.

[4] Park KY et al. Kimchi and an active component, beta-sitosterol, reduce oncogenic H-Ras(v12)-induced DNA synthesis. J Med Food. 2003 Fall;6(3):151-6.

[5] Kim HJ et al. 3-(4′-hydroxyl-3′,5′-dimethoxyphenyl)propionic acid, an active principle of kimchi, inhibits development of atherosclerosis in rabbits. J Agric Food Chem. 2007 Dec 12;55(25):10486-92.

[6] Kim YS et al. Growth inhibitory effects of kimchi (Korean traditional fermented vegetable product) against Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus. J Food Prot. 2008 Feb;71(2):325-32. Sheo HJ, Seo YS. The antibacterial action of Chinese cabbage kimchi juice on Staphylococcus aureus, Salmonella enteritidis, Vibrio parahaemolyticus and Enterobacter cloacae. J Korean Soc Food Sci Nutr 2003, 32:1351-1356.  Hat tip Rafael Borneo,

[7] Zhang YW et al. Effects of dietary factors and the NAT2 acetylator status on gastric cancer in Koreans. Int J Cancer. 2009 Jul 1;125(1):139-45. Nan HM et al. Kimchi and soybean pastes are risk factors of gastric cancer. World J Gastroenterol. 2005 Jun 7;11(21):3175-81.

[8] Lee SA et al. Effect of diet and Helicobacter pylori infection to the risk of early gastric cancer. J Epidemiol. 2003 May;13(3):162-8.

[9] Seel DJ et al. N-nitroso compounds in two nitrosated food products in southwest Korea. Food Chem Toxicol. 1994 Dec;32(12):1117-23.

Paleofantasy and the State of Ancestral Science

NOTE:  PaleoFX is coming up quickly and my talk will be related to some of the issues discussed below. It’s going to be a fun meeting. If you’d like to attent, buy a ticket or try your luck in FastPaleo’s PaleoFX ticket giveaway.

Marlene Zuk is an evolutionary biologist at the University of Minnesota, and her Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live is an important milestone for the Paleo movement: professional evolutionary biologists and anthropologists are now responding to Paleo ideas.

I haven’t yet read Paleofantasy but I have read:

Of the reviews, John Hawks in Nature is the most useful. Most Paleo community members have taken the term “Paleofantasy” as an attack upon the Paleo diet and lifestyle – as an assertion that our views conflict with reality – but Hawks suggests another take:

Zuk’s use of the term ‘fantasy’ is just an emphatic way of describing the hypothesis-forming that is essential to evolutionary science. We play with hypotheses, explore their predictions and try very hard to falsify them. So it is, in a way, unremarkable that so many hypotheses proposed by anthropologists about ancient environments now seem to be wrong — and, in a few cases, even ridiculous. [1]

The title “Paleofantasy” may sell more books than “Paleohypothesis,” but the latter is undoubtedly more accurate. The Paleo movement is based on a scientific hypothesis, and exploring its validity is a very reasonable thing for an evolutionary biologist to do. The ancestral health community should be flattered, not offended, that its science is being engaged by other scholars.

The Paleo Hypothesis

What is the Paleo hypothesis? The original version was expounded by Melvin Konner, Boyd Eaton, and others in the 1980s and 1990s. Here is Melvin Konner’s (2001) summary:

One approach, applied by Eaton and colleagues since the mid-1980s, is to consider the environment of evolutionary adaptedness for our species and to view it as the shaper of the latest draft of our genome…. This approach leads us to the discordance hypothesis, which attempts to assess the disjunction between those environments and the ones we live in now … [S]everal important chronic degenerative diseases have been interpreted as “diseases of civilization” because they appear to result from this disjunction. [2]

I’ve bolded the key ideas: that humans have an “environment of evolutionary adaptedness” approximately represented by the Paleolithic, and that multiple diseases result from a discordance between the modern and Paleolithic environments.

To operationalize the Paleo hypothesis, one must identify a modern implementation of the Paleolithic diet and lifestyle – not necessarily a complete re-enactment, but mimickry in essential elements. The most influential operationalization was created by Loren Cordain in The Paleo Diet (2002) and subsequent popularizers such as Robb Wolf tracked his diet closely. Their advice can be found on Cordain’s “What to Eat” and Wolf’s “What is the Paleo Diet?” pages: eat meat, fish, eggs, nuts, fruit, and vegetables; eschew starches, dairy, and some other foods.

A Target-Rich Environment

Both the Paleo hypothesis and its popular operationalization are vulnerable to challenge.

Most vulnerable is the operationalization by Cordain. It consists of an odd mix of foods. The meats, in accordance with archaeological evidence, derive mostly from grassland herbivores, while the plant foods – nuts, fruits, and vegetables – come largely from forest plants – trees. It is almost as if the evolutionary picture was that humans are chimps who learned to hunt, and our ancestors would dwell in the forest like chimps when foraging for plants but commute to grasslands to hunt animals.

This view drives Paleo toward a low-carb diet, since modern domesticated fruits and vegetables generally have only 50 to 200 carb calories per pound, and Paleolithic fruits and vegetables had even less. It would not have been easy for Paleolithic hominids to gather and eat many pounds of forest plant foods per person per day – especially when bipeds are not suited for getting fruit and nuts out of trees, and much of the band would have been hunting animals in a sparsely-treed semi-open grassland!

Not surprisingly, anthropological evidence has found that Paleolithic diets were quite different from the meat, fruit, and vegetables diet. There is little doubt that in the Paleolithic, starchy plants were a more important source of carbohydrates than fruits, just as they are among modern hunter-gatherers.

What is interesting about Zuk’s work is that she takes on the theoretical part of Paleo – the hypothesis of modern discordance with an environment of evolutionary adaptedness. Many in the Paleo movement take this as foundational, so if it were rebutted then one might think it would call into question the whole ancestral health movement.

Zuk’s Critique of the Paleo Hypothesis

Zuk’s critique strikes me as sound but disappointingly unambitious.

The Chronicle excerpt focuses on the persistence of evolutionary change:

[I]t is easy to assume that evolution requires eons. That assumption makes us feel that humans, who have gone from savanna to asphalt in a mere few thousand years, must be caught out by the pace of modern life …

[D]iscoveries like [the timing of the development of lactase persistence] make it clear that we cannot assume that evolution has stopped for humans, or that it can take place only ploddingly, with tiny steps over hundreds of thousands of years. In just the last few years we have added the ability to function at high altitudes and resistance to malaria to the list of rapidly evolved human characteristics …

Gregory Cochran and Henry Harpending even suggest that human evolution as a whole has, on the contrary, accelerated over the last several thousand years …

In one way Zuk is understating her point. Human genetic change did accelerate significantly over the last 10,000 years, due to rising populations which introduce new mutations to the human genome more frequently [3], and due to changes in selection pressure resulting from the establishment of large-scale societies following the domestication of animals.

Yet in another respect she is exaggerating it. The time required for favorable mutations to spread through the human population hasn’t shortened much since the Paleolithic. Even the most strongly selected recent mutations, such as that for lactase persistence, have spread only partially through the world’s peoples. There has certainly been insufficient time for the rest of the genome to evolve to an equilibrium with recently introduced mutations.

Yet, in the Paleolithic, the ancestral diet was probably similar in general outline for at least 2 million years: it consisted largely of meat, marrow, and plant foods collected from open woodlands and tree-spotted grasslands. There was sufficient time for new mutations to appear and rise to fixation, and then new mutations to appear and reach fixation against this new genetic background, and so on for many cycles. It is certainly possible that humanity became adapted to this (slowly changing) Paleolithic diet, and that the genetic variety introduced in the Holocene has been insufficient to destroy our fitness for a diet like that of the Paleolithic, and insufficient to make us well adapted to new Neolithic diets.

This point – that the relevant time-scale for assessing adaptedness may be the time for the genome to reach equilibrium, not merely the time for new point mutations to appear and grow to regional prominence – is an elementary one in evolutionary biology, one that is made in our book on pages 4-6, but from the Chronicle excerpt and various reviews (including this Amazon reader review), it appears that Zuk does not acknowledge this reason why treating the Paleolithic as an environment of evolutionary adaptedness may be a “Paleoinsight,” not a “Paleofantasy.”

Nor is it necessarily the case that adaptedness to the modern environment is assured by rapid recent evolution. To illustrate my point: a diet of Twinkies and Coca-Cola could never be healthful, and could never become our optimal diet, no matter how many billions of years we spent adapting to it. It simply lacks the nutrients needed to support sophisticated life.

So Zuk’s major points – that evolution has been a process of continuous change, never reaching a stable equilibrium; and that Paleolithic environments were diverse, making it difficult to specify an environment of evolutionary adaptedness or establish modern discordance with it – do establish that the Paleo hypothesis is not automatically trustworthy and needs to be supported in any given application by specific evidence. But she did not prove that it is never useful. It may guide us to a better diet and lifestyle.

Entertaining, But Unambitious

From reader reviews, the verdict emerges that Zuk wrote an entertaining book, using “Paleofantasies” as hooks on which to hang interesting facts, observations, and insights from evolutionary biology.

But most Paleo readers seem to have wanted a more ambitious undertaking. Most Paleo reviewers seem to agree with Theodore Roosevelt, who taught that in science

It is not the critic who counts … The credit belongs to the man who … strives valiantly, who errs and comes up short again and again, … who spends himself for a worthy cause; who, at the best, knows, in the end, the triumph of high achievement, and who, at the worst, if he fails, at least he fails while daring greatly … (“Citizenship in a Republic,” speech at the Sorbonne, Paris, April 23, 1910)

Evolutionary biology has much to teach us about how we should eat and live for best health. It would be good for evolutionary biologists to spend themselves for the worthy cause of identifying those truths.

What Does the Paleolithic Tell Us About Our Optimal Diet?

Coincidentally I came across a TEDx talk on Paleo diets by archaeologist Christina Warinner that makes a creditable effort at providing an alternative operationalization of a “Paleo diet.” Ignore the first three minutes in which she calls Paleo a fad diet based on meat; the latter part of the talk is excellent.

She makes the excellent point that domesticated plants have been bred for reduced toxicity. We may now be able to eat a much healthier diet than was possible during the Paleolithic, thanks to reduced-toxicity plant foods.

Warinner suggests the following modern operationalization of the “Paleolithic diet”:

  1. Eat a diet high in species diversity. Do not, as Americans do, concentrate plant consumption among a mere three species: corn, soy, and wheat.
  2. Eat fresh foods. Stored food loses nutrients and spoils; preservatives that inhibit microbial growth may disturb our gut microbiome.
  3. Eat whole natural foods; avoid refined processed foods. Natural foods have a full package of nutrition and healthful fiber. We should not indulge our new-found ability to consume sugar far more rapidly than would have been possible in the Paleolithic.

These are all points we make in Perfect Health Diet:

  • The benefits of diets high in species diversity are discussed in chapter 24 – because “the dose makes the poison,” diverse diets prevent toxins from becoming poisons.
  • The benefits of eating “recently living plants and animals” rather than processed foods constructed of purified nutrients are discussed in chapters 2, 8, and 23.

Warinner’s three recommendations are an excellent start toward a healthy diet. It’s good to see a scholar venturing to make prescriptive suggestions.

Yet I think that evolutionary biology can tell us much more than this. To see what it teaches, we have to broaden our perspective beyond the Paleolithic and the original “Paleo hypothesis,” and venture into biology.

Maybe “Paleo” Should Stand For Paleozoic Diet

One of the novel insights of Perfect Health Diet is that the evolutionary roots of the optimal human diet are ancient – they extend back to the start of the Paleozoic Era 541 million years ago when a great flourishing of multicellular life took place.

The rise of multicellular life depended on the use of carbohydrates to glycosylate membrane proteins and to form a carbohydrate-rich extracellular matrix to support multicellular structures. This increased use of carbohydrate was the last major change in the macronutrient composition of life. As life feeds on life, it represented the last major change in food.

In Perfect Health Diet, we discuss a number of evolutionary patterns determined by evolutionary selection and indicative of our optimal diet:

  1. Until bodily protein is depleted, all animals tolerate fasting quite well. This is because the composition of the body closely resembles the composition of our optimal food, so that self-cannibalization is nourishing.
  2. Breast milk has a similar composition in all mammalian species. This is because all mammalian species – whether herbivore, carnivore, or omnivore – need the same nourishment.
  3. Evolution doesn’t modify the body’s composition in order to exploit a new environmental niche, but rather modifies the digestive tract’s ability to transform novel foods into the desired nutrient mix. Herbivores, carnivores, and omnivores have similar nutritional needs and similar bodies; only their digestive tracts differ. The digestive tract is evolutionarily “plastic” in a way the rest of the body is not.
  4. In humans, the brain’s food reward system is an important guide to our most healthful diet. As dominant hunters and skillful foragers, ancestral humans had their choice of foods. Mankind’s Paleolithic evolution developed a food reward system that helps us choose an optimal mix of foods, and that brought us a diet that required minimal transformation by the digestive tract, enabling digestive organs to shrink. This is Aiello and Wheeler’s “expensive tissue hypothesis” [4], re-interpreted.

From this perspective, the optimal human diet was determined 541 million years ago, at the start of the Paleozoic, when the composition of animal flesh was more or less fixed. From that point forward, it was evolutionarily inevitable that as soon as a creature became able to “rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals, and over all the creatures that move along the ground” (Genesis 1:26), so that the whole world became its buffet table, this creature would lose its expensive digestive tract and gain a brain capable of guiding it to a healthful pattern of eating.

Our optimal diet is deeply constrained by our biology; it does not vary in any environment. Environmental changes that bring a new dietary niche force evolutionary changes to our food reward system and our digestive tracts, but they do not change the optimal human diet – one that, like breast milk, is little altered by evolutionary change. Because our body composition is evolutionarily stable, the mechanisms by which we select our foods and transform imperfect diets into something better are changed; not the mix of nutrients we need.

I like the name “Ancestral health movement” better than “Paleo” because it is less specific about whether there was a specific time of evolutionary adaptedness, or when that was. In truth, different organs of the body reached evolutionary adaptedness at different times – some as far back as 541 million years ago.

But from another perspective, “Paleo” is quite fitting. The Perfect Health Diet is truly “Paleo” – in the sense of Paleozoic, not Paleolithic.


The Ancestral Health Society is forming a new scholarly journal, The Journal of Evolution and Health, to complement its annual Symposium.

It is coming at a good time: when scholars have begun to appreciate the significance of the Paleo/Primal/PHD/Ancestral movement, yet remain unfamiliar with its recent scientific and intellectual developments.

Yes, the scientific hypotheses on which “Paleo” began were flawed (though insightful and scientifically productive); but a newer and better scientific foundation has been developed.

The Ancestral health movement has become popular because it works: it truly does heal and prevent disease, and millions have experienced its benefits. So it is no fad diet, and will not fade away.

I hope that scholars like Zuk and Warinner will continue their engagement with the ancestral health movement, and help us refine the science still more.


[1] Hawks J. Evolutionary biology: Twisting the tale of human evolution. Nature. 2013;495(7440):172 – 172.

[2] Konner M. Evolution and our environment: will we adapt? West J Med. 2001 May;174(5):360-1.

[3] Hawks J, Wang ET, Cochran GM, Harpending HC, Moyzis RK. Recent acceleration of human adaptive evolution. Proc Natl Acad Sci U S A. 2007 Dec 26;104(52):20753-8.

[4] Aiello LC, Wheeler P. The expensive tissue hypothesis: the brain and the digestive system in human and primate evolution. Current Anthropology 1995 Apr;36(2):199–211.