UPDATE: The new edition has launched! Books are in stock and shipping. Here is the Amazon page.
Readers of our first edition, like Steven, are naturally wondering what’s new in the Scribner edition.
There’s a lot that’s new. The Scribner edition is 50% longer; almost half of the material is new. Original material is revised and updated.
In a series of posts this week, I’m going to walk through the book and discuss what’s new and original. This post is about Part I, “An Evolutionary Guide to Healthful Eating.” (You can see a Table of Contents for the whole book on our Notes page, or in the Scribd excerpt below.)
Paleolithic Diets: An Evolutionary Story
Loren Cordain uses a striking analogy: he compares the length of the Paleolithic, 2.6 million years, to the length of a football field, 100 yards. By that scale, the Neolithic – the period when grains and farmed foods became a major part of our diet – is about a foot long. The point is that, in evolutionary terms, our relationship with agriculturally mass-produced cereal grains has been relatively short (to say nothing of our relationship with high-fructose corn syrup and soybean oil!). It stands to reason that we’d be adapted to the diet and lifestyle of the Paleolithic, and we agree, for reasons discussed in Chapter 1.
But what was the composition of Paleolithic diets? The Paleolithic was the era of stone tool use, and one of the primary purposes of stone tools was butchering animals, so the Paleolithic roughly corresponds to the period when meat was a significant part of our diet. But plants were also a major part.
The popular Paleo movement presents a fairly consistent view of what a “Paleo diet” is: meat and fish, fruits and vegetables, nuts and seeds. But how close is this “Paleo diet” to actual Paleolithic diets? Did Paleolithic peoples forgo starches? Did they eat almond meal waffles, muffins, and cookies? Looking into the actual Paleolithic diet is the subject of Chapter 2.
Unfortunately, the standard Paleo “evolutionary” argument doesn’t get us very far toward finding the optimal human diet. First, there was no one Paleolithic diet: it varied considerably by time and place. Second, the contention that our hunter-gatherer ancestors “adapted” to the diet they were eating and were optimized for it is open to question. Our biology is not infinitely malleable, capable of adapting to any diet. We could subsist on Twinkies for 2.6 million years, and Twinkies would never become the optimal human diet. How can we know that plants and animal foods gathered and hunted in the Paleolithic were then, or are now, our optimal diet?
Fortunately evolutionary evidence tells us much more about what is healthful for us, and what it tells us is supportive of the Paleolithic diet story.
A Richer Evolutionary Story
Evolution selects every aspect of our biology – how cells work, how organs work, how our brain works.
In the first edition, we gave a few very brief summaries of some alternative evolutionary arguments for the optimal human diet. We found that even very smart readers often misunderstood or didn’t appreciate the strength of these arguments, so we elaborated on them in the new edition.
These arguments are spelled out in Chapters 3-6: The “Cannibal Diet” of Fasting, What Breast Milk Teaches Us About Human Diets, What Mammalian Diets Teach Us About Human Diets, and The “Tastes Great!” Diet.
Why does fasting tell us about the optimal diet? Think about how food is handled. Our food doesn’t go straight from our digestive tract to our mitochondria to be turned immediately into energy. Instead, nutrients from food are incorporated into tissue within a few hours after a meal, and then that tissue is cannibalized to supply energy needs over the following 24 hours.
As a rule, tissues won’t accept just any macronutrients. Cells have a very specific structure, with fatty membranes and protein-rich cytosols; and they have very specific fatty acid profiles in their membranes, and amino acid ratios in their proteins. Cells specifically take up nutrients in the proportions they need, and refuse to incorporate nutrients they don’t need.
So if we evolved to be nourished by self-cannibalization of tissue, then the nutrient composition of our tissues must be close to our optimal diet.
What about breast milk? Most people will agree that this is the optimal food for infants. But many have thought there must be so many differences between infants and adults that breast milk will tell us little about the adult diet.
Not so. We can quantify the differences between infants and adults – they have mainly to do with the large and fast-growing infant brain – and can see which parts of the breast milk are designed to support that brain. We can adjust for those differences, and estimate the optimal adult diet from the composition of breast milk.
What about mammalian diets? I think this is one of the most interesting parts of our book and will be of great interest to pet owners, farmers, veterinarians, zookeepers, and anyone who has to feed animals.
The reality is that evolutionary selection has been operating for far longer than the Paleolithic, and it settled on certain solutions quite early. Multicellular life was common by 500 million years ago, and the basic composition of cells and their extracellular matrix scaffolding hasn’t changed much in that time.
So if our cellular biology hasn’t changed much in 500 million years, then the nutrients needed by cells hasn’t changed much either. That means the optimal diet hasn’t changed much. Yet there is a diversity of animals that occupies every possible ecological niche and type of food. How can a common biology be fed by a diversity of diets? Why are there herbivores, omnivores, and carnivores?
The resolution of this seeming paradox lies in the digestive tract and how it transforms food into nutrients. This allows us to infer from the digestive tract what an animal’s optimal diet is. We can do that for humans, too.
Those three evolutionary arguments were present in capsule form in the first edition, but the next one is entirely new to this edition: a discussion of the food reward system of the brain. Food reward evolved to motivate us to go seek out healthy, nourishing foods. If it evolved in the Paleolithic environment, then it tells us what foods were hard to get in the Paleolithic, but still necessary for health – these were the foods that Paleolithic foragers had to be motivated to work for.
But in our modern world, all foods are easy to obtain; they are on the shelves of supermarkets. So those foods that were hard to get in the Paleolithic are going to be precisely the ones that we overeat today.
The presence of an innate food reward system explains why peoples around the world eat very similar diets – almost always 50% carb, 15% protein, 35% fat, or close to it. If this food reward system evolved for the Paleolithic food environment, which was radically different from the modern agricultural and industrial global food production system, then we can’t trust our unconscious food buying impulses. If we just go to the supermarket and put whatever seems desirable into our cart, we will overeat all the things that our Paleolithic ancestors tended to undereat.
Worse, we will be tempted to eat junk foods designed to appeal to the tastes that signal healthfulness to the food reward system, without supplying the nutrients that actually deliver healthfulness.
On the other hand, this evolutionary argument is encouraging. It tells us that, if we eat Paleolithic foods and if we educate ourselves to select healthy foods in the optimal proportions, then we can be confident that our brains will find our meals to be delicious and satisfying.
A healthy diet is also a delicious and satisfying diet! There is no need to suffer to be healthy. There is no need to suffer to lose weight. If you are suffering on a diet, you are doing something wrong.
Part I ends by circling back to a recurring topic: animal diets. Our pets, zoo animals, and even feral rats living in urban areas and eating our trash are partaking of our ill health. They are becoming obese in parallel with us, and develop cardiovascular disease at similar rates; their wild counterparts do not have these problems. Yet returning zoo animals to their natural diets returns them to good health. Adopting our natural diet works for humans too. Our Perfect Health Diet reader success stories support this claim.
Evolutionary Fine-Turning
The rest of the book also puts some weight on evolutionary arguments. When we look at individual nutrients, we find that the body has evolved mechanisms to bring them close to an optimal level:
- The body adjusts toward an optimal carb intake. When carb intake is too high, glucose is converted to fat. When carb intake is too low, glucose is manufactured from protein. The Goldilocks level, at which the body neither manufactures nor disposes of glucose, is an indicator of the optimal carb intake.
- The body adjusts toward optimal fatty acid proportions. In Americans today, omega-6 fats are more than three times more likely to be burned for energy than saturated fats. Yet on omega-6 deficient diets, omega-6 fats are less likely to be burned for energy than saturated fats. This evolved system for regulating the body’s fatty acid composition is clear evidence that Americans eat too many omega-6 fats and too few saturated fats.
Similar arguments from evolutionary biology guide us toward optimal intake of micronutrients, which have degradation or excretion pathways turned on when they are present in excess, and conservation pathways turned on when they are scarce.
Cooperating with Our Bodies to Build Health
The earliest human temptation, if we are to believe the story of the Garden of Eden, was to “be as gods” and define good and evil — healthful and unhealthful — for ourselves. There is an undoubted attraction, we have felt it ourselves, to masterminding our diet and nutrition. We like to think that evolution got it wrong, or optimized for the wrong thing, and that an extreme diet or unnatural intervention can improve our health.
It’s not just extreme dieters who think this way. What is the pharmaceutical model of medicine, but the idea that we can alter the natural functioning of our bodies in ways that will make us healthier?
Sometimes this can work, but usually wisdom and deeper knowledge show us that evolution got it right, that our innate biology works to maintain our health rather than harm it, and that interventions which subvert natural functions tend to do more harm than good.
A more promising approach, we think, is to cooperate with our bodies. This leaves plenty of room for medicine to help – through diagnosis and testing, through antimicrobial treatments, through integrated dietary and lifestyle advice, and through interventions that support natural bodily functions (as, for instance, thyroid hormone replacement in hypothyroidism, or insulin therapy in type 1 diabetes).
It’s this cooperative approach, integrating the best of medicine with the best ancestral health practices, that we think will be most effective at generating good health and long life. We hope our book will illuminate what those “best ancestral health practices” are, and help build a cooperative effort between the natural health movement and the medical community.
Concluding Thoughts & a Book Excerpt
It could be said that our book is an “owner’s manual” for the human body, helping our readers know how to best support their own health by living in accord with our evolved biology.
The great thing is, the way to do this is by eating delicious, satisfying food!
If you’d like to get a feel for the book, check out this excerpt, which Scribner has put on Scribd:
PERFECT HEALTH DIET: How anyone can regain health and lose weight by optimizing nutrition, detoxifying the…
via this link:
Sorry if I missed this elsewhere, but are there any plans for an audiobook version? I have a family member who would probably thoroughly enjoy this book and benefit from it but, due to traveling frequently by car for work, has little time for regular books yet much time for audiobooks.
Hi Amelia,
I don’t know. That will be up to Scribner. It probably depends on how well it sells.
Should I expect the book to come out in Jan/Feb in the UK?
Yes. I’ll announce a more precise timetable when I have it.
I’ll be interested to see if your “Goldilocks level” of carbs theory pans out. However, there are many animals that seem to live out pretty long lives on diets that don’t match tissue composition much. Pandas who eat bamboo and whales who eat krill come to mind.
Here’s the thing, we just don’t know yet if it is better for our bodies to manufacture fat vs eating it. And we basically know that it definitely better for us to manufacture our own fat then to overconsume omega 6 fats.
I def look forward to move of your posts on this!
Hi Aaron,
One clue is that the breast milk of all mammals closely matches infant tissue needs. It doesn’t ask the infant’s body to manufacture its own fat or glucose.
Couldn’t is simply be evolutionary insurance because some of the infant’s organs are still immature?
Perhaps … but maybe we benefit from insurance at all ages.
Breast milk without question is a great food for a growing baby. Not exactly sure we can make the leap to an optimal ratio for a human who is just trying to maintain itself vs the needs of a growing baby.
Without posting any studies — I think it has been quoted before that castrated males live longer and are shorter than the average male. In effect, there are longevity benefits to a lack of growth factors. (think male female differences too)
The magic ratio that makes babies grow so well might not be optimal for someone who just wants to maintain tissue — like I usually say, we need more studies.
Fat intake affects SHBG <– hope I got that right. Part of the magic in a lower fat diet is higher SHBG. I love fat but unless you keep carbs at ketogenic levels, SHBG drops sharpy when you start increasing carbs AND FAT. More and More I believe you eat to optimize hormones <—-
Lastly, for myself, I don't know how I overlooked my non-secretor status when I got a genetics test. Starting to make sense why so many foods in general give me such problems. Personally, I eat more primally because it gives me more stable energy than any kind of optimization for longevity — <<— I'm looking to other methods for that.
Hi Aaron,
Interesting thoughts. Thanks.
SHBG is an interesting topic. In general I don’t put much stock in identifying particular levels of hormones or hormonal regulators as targets. With hormones everything is context dependent. SHBG is reduced more strongly by protein than by carbs or fat, eg http://jcem.endojournals.org/content/85/1/293.full. Energy-restricted diets increase it, energy-excess diets reduce it. Since all macronutrients reduce SHBG, I don’t think you can say that trying to increase it in isolation is better.
As always, thank you for taking the time to respond!
Did you happen to take a look at this study which was footnote 13 from the study you mentioned.
http://jcem.endojournals.org/content/64/5/1083.abstract?ijkey=c0053adb13c7c5efa2fd67353880368be1cf30a3&keytype2=tf_ipsecsha
It shows a decrease in SHBG for men consuming over 100 grams of day a day and a decrease for those consuming less than 20 a day. Doing the math, those people were probably getting around 50% fat if you have a diet around 2000 calories (give or take). Now, at perfect health diet levels of 60-70% fat I wonder what we could extrapolate.
For me, I’d def trade some strength for longevity as long as I could maintain some muscle mass for daily activities and illness.
Like you said though — we don’t know how all the hormones fit in. But I think a reduction of testosterone in context may be a good thing!
Hi Aaron,
I haven’t reviewed the studies but I suspect it’s more connected to total calories than fat calories.
Any short-term restricted diet is going to tend to be lower in calories, until people start getting hungry. 20 g fat/day is definitely lipid deficient.
Our claim is that PHD minimizes calorie intake while eliminating appetite, so it would tend to have the opposite effect to the high-fat diets in these studies.
Would be interesting to test this. But it’s mainly of academic interest, because as I said there are many more variables to consider than SHBG, and I doubt SHBG levels by themselves are a useful indicator of optimal.
A major difference between PHD and breast milk is that half the carbohydrate in milk is galactose, and this is comparable to fructose in that it is preferentially taken up by the liver leaving glucose in circulation.
http://www.ncbi.nlm.nih.gov/pubmed/1733250
“The metabolic quotient for galactose increased significantly after feeding, such that galactose was the largest carbon contributor for postprandial hepatic carbon accretion. After a milk feeding, the newborn liver efficiently extracts galactose, lactate, and oxygen, but not glucose.”
I’m presuming that the lactate and galactose are used to supply glycogen and some fat, and the glucose is spared for the brain and muscles, from which the latter also supply more lactate.
I really enjoyed the excerpt. Nice prose style and just the right tone.
Hey Paul,
Amazon hasn’t got the new book listed as available in Kindle format yet. Will this be available on the day of the release?
Many thanks,
Kristopher Cleary
I am a skeptic by nature and see some opposing conclusions here but I think the question never asked about food reward is a simple one.
Did we develop a food reward system as a survival mechanism? Or did plants develop the ability to exploit a human weakness to win the war of evolution via a “long term strategy”.
Does food reward actually motivate anyone to eat anything in an “isolated tribe” environment? Or did it explode simply because Nabisco and Hostells got in on the act? It seems to me isolated tribes are remarkably disciplined about what they eat, putting sustainable food management well ahead of the desire to snack. The kitavins would not have gotten past their first generation on a small island with limited food resources if they did not exercise some self control and resist eating all day long, which they could certainly have done with all that leisure time they enjoy.
Hi Danny,
Let me see if I understand. You’re saying that humans are naturally carnivores, but plants evolved a mechanism for seducing humans (though not lions, tigers, hyenas, or wolves) into eating plants?
Or that the food reward system was innocuous and had no evolutionary reason to exist in the Paleolithic, but that it is now exploited by junk food manufacturers to damage health so its only historical effect has been negative?
I think peoples like the Kitavans eat to appetite and restrict fertility. In the event they don’t restrict fertility, murder takes care of a surplus. It is not refraining from eating that prevents them from outrunning their resources.
I suspect “all that leisure time they enjoy” doesn’t exist. They work every day to survive and thrive. Sandals Vacations presents an illusion.
In anthropology, island fishing tribes are called “sedentary cultures”. I think there might be something in that. In a hot place, and in a salty place where water or other electrolytes might be limited, would you exert yourself more than necessary?
Hi Paul,
Just bought four more copies as holiday gifts. So thanks not only for improved health but for efficient shopping.
Paul, it was so wonderful to meet you at AHS, even if ever so briefly. Congratulations on the new edition and thank you so much for keeping everything up to date and relevant.
I have your first edition and I’ll be buying this one, too! I am getting completely overwhelmed by ‘paleo’ books, but that’s a first-world problem, eh? 🙂
Hi Paul,
I’m curious your thoughts on if goat milk is okay from a casein perspective, since it has A2 beta-caseins and is thought to be more similar to human breast milk?
Thanks,
Mark
Hi Mark,
It does seem to be quite a bit better tolerated than cow’s milk.
Paul, I thought you said earlier that you were making a cookbok that was about to be published soon. Am I wrong?
Hi Acai,
Yes, we’re working on a cookbook, but progress has been delayed due to our book launch. We will focus on the cookbook in the new year.
OK, great. I look forward to it. I also forgot to say congratulations on the new edition of your book!
My book shipped today 😀
I made a request to Audible.com for an audiobook version. I would suggest others to do the same. I’m sure they would respond if there is interest
Hi Paul,
Any idea why the kindle version is more expensive than the hardcover version? I own a copy of the original book and want to update, but would prefer a kindle version if reasonably priced.
thanks
Hi DancinPete,
The Kindle version is still cheaper, $14.99 vs $16. I don’t know why prices are chosen, and how much is Amazon and how much the publisher.
Hi Paul, FYI: I show the kindle version at $18.98 vs hardcover at $16.61 on amazon.com. Not that I want to quibble over a few bucks, but there’s no way amazon can justify selling a kindle version for more than a hardcover version. Perhaps it has something to do with me being in Canada.
In Australia we don’t even have the Kindle option for the PHD book on amazon.com. I hope that will change when the Aus edition is released.
for what is worth you can see the kindle edition option on http://www.amazon.ca when viewed from Australia
Still the US edition of course.
Aus edition due for release in January,
http://scribepublications.com.au/books-authors/title/perfect-health-diet/
Adam,
Just change your Amazon address to a US address just for buying the PHD. You’ll be able to buy it then!
Kristopher
Thanks Darrin – unfortunately when I try to purchase it form there it says not available in your country.
Hi Paul, congratulations on the new version.
“…It stands to reason that we’d be adapted to the diet and lifestyle of the Paleolithic” –among other things, given the rate of genetic change in our exponentially growing population and its potential cascade effects in a complex system like human biology, this actually strikes me as a non sequitur.
“if we evolved to be nourished by self-cannibalization of tissue, then the nutrient composition of our tissues must be close to our optimal diet” and why would that follow? so easy to think of various potential reasons for alternatives (eg. the optimal fuel for my car: plastic and metal)
“We can quantify the differences between infants and adults … and estimate the optimal adult diet from the composition of breast milk.” Paul, you never seem to properly address the issue of growth versus maintenanance here. “Insurance” for example doesn’t really cut it.
Hi donat,
The essentials are discussed in the excerpt. We haven’t had time to become adapted to anything else. So some may have acquired mutational load that makes them maladapted to any environment; but no one has become well adapted to some alternative environment.
The infant-adult issue is addressed in Chapter 4 of the book.
Paul, thanks for your reaction. Why do you say that “We haven’t had time to become adapted to anything else”? Any evidence for this claim? It is certainly not self-evident and in fact it does not seem to be true.
E.g:
“Genomic surveys in humans identify a large amount of recent positive selection.Using the 3.9-million HapMap SNP dataset, we found that selection has accelerated greatly during the last 40,000 years. …Larger populations generate more new selected mutations, and we show the consistency of the observed data with the historical pattern of human population growth. We consider human demographic growth to be linked with past changes in human cultures and ecologies. Both processes have contributed to the extraordinarily rapid recent genetic evolution of our species.”
Hawks, J., E. T. Wang, G. M. Cochran, H. C. Harpending, and R. K. Moyzis. 2007. ‘Recent acceleration of human adaptive evolution.’ Proceedings of the National Academy of Sciences 104:20753-20758. doi: 10.1073/pnas.0707650104
*****
Actually, my point about the infant-adult issue was not that you did not discuss it.
Hi donat,
Positive selection is one thing, fixation is another, full adaptation is yet a third. Positive selection could mean that it’s increasing from 0.00001% of the population to 0.00002%. Fixation means the allele has spread throughout humanity. Full adaptation means not only the allele has spread, but the genetic background which accommodates and promotes its good effects.
The Neolithic mutation that’s spread the most is lactase persistence, and no one allele for that is found in more than a small fraction of humanity.
I think Chapter 4 of the new edition addresses the growth vs maintenance issue.
My point is that various HapMap based papers indicate that we are all quite genetically different from our paleo ancestors. Fixation of X seems relevant here only to the different issue of whether individuals in the current population are similar to each other in X.
Full adaptation in particular certainly need not presuppose fixation.
I really don’t understand the paleo concept. Let’s say generously that the paleolothic for humans was 150-200 times the 10k years of neolithic. Given a paleo population between say 6k and 30k, lets say a very generous 20k we get to compare paleo 3-4M to neolithic say approx. 3500 M (half of current 7000M, starting from around nil) giving us a 1000fold difference in human-years for genetic change to operate in, in favour of the neolithic. Rough, but more like 10 football pitches end to end.
Donat, I don’t believe you are looking at this from the right perspective (I could be wrong). The forces of nature are more likely to exert change on a smaller population than on a large one, so your example is actually supportive that the paleolithic has more “shaping” power on the human traits at any given time than the neolithic. Now, add up all this up as units of time, not population.
“The forces of nature are more likely to exert change on a smaller population than on a large one” Could you clarify? I’m not sure why one would think that this is the case?
Smaller populations are more subject to genetic drift, that’s probably what he means.
Hi donat,
Again, read the excerpt. There are 300,000 chimpanzees today, it’s likely the ancestral population was at least as large through most of the Paleolithic. And while population-years is a good indicator of the number of mutations, those mutations need time to propagate through the population, find a genetic background that is favorable to them, and be subject to selection. That takes hundreds of thousands of years. The Paleolithic had it, the Neolithic doesn’t.
(1)”There are 300,000 chimpanzees today, it’s likely the ancestral population was at least as large through most of the Paleolithic.”
(2)”mutations need time to propagate through the population, find a genetic background that is favorable to them, and be subject to selection. That takes hundreds of thousands of years”
There is quite a bit of evidence around that these assumptions are not likely to be true.
(1) is not an assumption, it’s the result of a census of wild chimpanzees.
(2) is true. It’s an exceedingly rare mutation that reaches fixation in tens of thousands of years. No Neolithic mutation is known to have reached fixation, not even lactase persistence.
Paul, are you pulling my leg?
(1) obviously I was not referring to the number of chimpanzees today, but to the number of our paleolithic ancestors. That it was “at least as large” is an assumption and I think probably incorrect. But never mind, 30k or 300k does not change my major point (relatively very small a population)
(2)again, you introduce a term ‘fixation’ that was not present in your earlier remark I commented on. You don’t define fixation, so I assume you understand it in such a way as to make your claim about it true. Fine. But that has little to do with what I said about your earlier remark. There is a growing body of evidence of Neolithic selection driven genetic evolution.
Apparently I was answering in the wrong sequence. You did in fact say how you understand fixation in a previous comment.
Love the intellectual banter it reminds me of my days as a university prof…talking heads wanting to be right.
Semantics aside, Paul’s commitment to scientific reasoning and research have made the PHD a breath of fresh air in the health/diet community. The proof is in the success of those of us on the PHD and the willingness of Paul to find answers and now updating his work with the new book. Much appreciated!
There are plenty of other “diets” to challenge donat…head over to the China Study, Forks over Knives, vegans, etc. They’re a cynic’s dream!
Hi donat,
Sorry for the misunderstanding about (1). If you’re thinking about effective population sizes in genetic models in the tens of thousands, typically actual population sizes are ten times the effective size, so an effective population size of 30k-70k is consistent with a 300k-700k ancestral hominid population.
I agree that there is a lot of selection going on in the last ten thousand years, especially the last two thousand years. But I don’t believe that has altered the optimal human diet, nor made us maladapted the Paleolithic diet.
We agree then that a lot of selection driven genetic change has taken place recently and presumably then also that therefore we are genetically quite different from our paleo ancestors. Do you assume that these genetic changes somehow for some principled reason (surely it would be too big and strange an accident to be accidental) have no (significant) bearing on what diet and lifestyle we are best adapted to? Recall that this discussion started with your claim that “…It stands to reason that we’d be adapted to the diet and lifestyle of the Paleolithic”
I admit I cannot see any principled reason for the genetic changes not to pertain to diet and lifestyle, if anything, reasons for the opposite come more easily to mind.
Donat, have you read the Scribd excerpt from the book? This has more material relevant to the issue.
Jan, the university prof, I am certainly one of those who appreciates Paul. But I don’t think adulation is the only form of appreciation. So that is precisely why I commented here and not on some of the other paleo sites.
I don’t want to be right I want to figure out who is right, and I assume Paul has the same attitude. Nothing cynical about that. But if you like, just feel free to take over from here increasing the confirmation bias factor. I fully understand that people have a very low tolerance for uncertainty and thus for disagreement.
Hello Mr. Jaminet,
Was wondering if you would care to comment on the Japanese wheat/IQ study over at Cochran and Harpending’s blog. Some of us are curious if the IQ effect is real and whether we understand anything about the mechanism. Mr. Harpending has mentioned you as an expert on the topic.
http://westhunt.wordpress.com/2012/12/03/reversal-of-fortune-2/#comment-5931
Hi observer,
I know Henry Harpending has read our book, we corresponded about it.
It is not easy to trace the many factors which impact IQ. Obviously, iodine deficiency has a huge effect. We know that wheat is more toxic than rice and we have the one study indicating that it may be a problem for IQ. I would not be surprised if omega-6 fats from vegetable oils are now dumbing down America.
I left a comment over there. Thanks for introducing me to the conversation, and cross-fertilizing ideas!
Christmas came early! I just got my book today and I am really excited about it. OK… maybe I am a little too excited. ha. Thank you Paul and Shou-Ching for all your hard work.
The book depository are selling the hardback copy in the uk.ordered today and they say they have a 100 copies,
Also the iBookstore has it for £8.99
Hope sales go well,I’m sure they will.
Old Europe (Germany) calling… The book arrived today. Amazon.de works fast. I am excited!
Cheers, guzolany
Enjoying the new edition! Where’s the best place to report typos? On p. 42 under the herbivores bullet point, “with even numbers of fatty acids” should presumably be “with even numbers of carbon atoms”.
Thanks, Dan. Good catch!
As my name suggests, I’m Scottish. And the flip between “paleo” and “neolithic” diets might be much nearer in time than you think. Studies (I can get the references if needed) show that the proportions of n-6 and n-3 in the Scottish diet flipped places after 1945. What’s more, I was having dinner with my parents-in-law (75 and 76) yesterday and they confirmed that “in the nineteen-seventies and eighties, we loved to give you kids all the sweeties (candy) and pastry and cakes we could never have in the thirties – we thought we were treating you to the high life…”
Need I say more…?
Hi Paul! I love your book. I am a big fan of intermittent fasting. But I sometimes get discouraged when I hear from “the nutritional experts” that it can lower your metabolism. They say that our metabolism drops during sleep overnight and that it is important to eat breakfast first thing in the morning to get our metabolism going for the day. Will you please address this? Thank you so much
Rick
First off I want to say great blog! I had a quick question in which I’d like to ask if you do not mind.
I was interested to find out how you center yourself and clear your thoughts before writing.
I’ve had difficulty clearing my mind in getting my thoughts
out there. I do enjoy writing but it just seems like the first 10 to 15 minutes are lost just trying to figure out how to begin. Any suggestions or tips?
Cheers!