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Monday, June 3, 2013

GCBC Reference Check ~ Part VIII of ? ~ The Paleo Diet

Preface:  When I first read GCBC some time in 2009, I skimmed over the parts that were irrelevant to my issues with the book, which were on the basis of Taubes' misrepresentations of metabolism and obesity, etc.  In the intervening years I've gone back and read large chunks of it in more detail, but if I ever read the parts about the Paleolithic, I didn't take much note at the time because the names were not familiar to me.  

I've always found it odd how Taubes was described as paleo in some circles, his book is even cited on an infographic listing 10 years of paleo literature!  Aside from calling out refined carbs and sugar quite a bit, Taubes doesn't really make much of a deal about quality of foods, especially fats.  (Shhhhhh, don't tell the paleo peeps, but peanut oil is listed as an "especially healthy" oil in WWGF - Kindle Locations 3423-3424)

Recently on my long ago and forgotten post inquiring if the Paleo Diet was VLC, Juliana left the following comment
Are you sure the fat intake was almost at "low fat levels?" 
It is so funny how one author refutes another!
Taubes says that according to anthropologists, our ancestors preferred the meat that had the higher amount of fat, which also happens to lions.. And why are they not fat?
I have since covered in more detail what the studies/scientists/authors most frequently cited have to say about the composition of the "Paleo diet" with The Paleolithic Diet According to S.Boyd Eaton and Melvin Konner - Version 2010, and just collecting the relevant papers in The Paleo Papers.  Between these and the paleo diets used in clinical trials, such as described in Two Paleo Diets from Lindeberg's Group, I think it's pretty clear that -- at least according to these sources -- the paleo diet is low fat.  Before I go on, I'm pretty sure Julianna added her commentary about the lions, Taubes does not mention them in GCBC (gotta love ebooks for searchability! Kindle location 629)  Interestingly, however, he does mention wild sea lions ... yes I know, not lions) and seals having naturally occurring atherosclerosis.  So anyway ...

I searched my GCBC and found that he did, indeed, address the paleo diet within the discussion on the history of the low fat guidelines.

By defining “biological normality” as “the conditions to which presumably we are genetically adapted,” Rose was saying that the healthiest diet is (presumably) the diet we evolved to eat. That is the diet we consumed prior to the invention of agriculture, during the two million years of the Paleolithic era— 99 percent of evolutionary history— when our ancestors were hunters and gatherers. “There has been no time for significant further genetic adaptation,” as the nutritionists Nevin Scrimshaw of MIT and William Dietz of the Centers for Disease Control noted in 1995. Any changes to this Paleolithic diet can be considered “unnatural factors,” and so cannot be prescribed as a public-health recommendation. The Paleolithic era, however, is ancient history, which means our conception of the typical Paleolithic diet is wide open to interpretation and bias. In the 1960s, when Keys was struggling to have his fat hypothesis accepted, Stamler’s conception of the Paleolithic hunter-gatherer diet was mainly “nuts, fruits and vegetables, and small game.” We only began consuming “substantial amounts of meat,” he explained, and thus substantial amounts of animal fat, twenty-five thousand years ago, when we developed the skills to hunt big game. If this was the case, then we could safely recommend, as Stamler did, that we eat a low-fat diet, and particularly low in saturated fats, because animal fats in any quantity were a relatively new addition to the diet and therefore unnatural. 
This interpretation, shared by Rose, was established authoritatively in 1985, the year after the NIH Consensus Conference, when The New England Journal of Medicine published a quantitative analysis of hunter-gatherer diets by two investigators— Boyd Eaton, a physician with an amateur interest in anthropology, and Melvin Konner, an anthropologist who had recently earned his medical degree. Eaton and Konner analyzed the diets of hunter-gatherer populations that had survived into the twentieth century and concluded that we are, indeed, genetically adapted to eat diets of 20– 25 percent fat, most of which would in the past have been unsaturated. Eaton and Konner’s article has since been invoked to support low-fat recommendations— in Diet and Health, for instance— as Rose’s argument suggests it should. But Eaton and Konner “made a mistake,” as Eaton himself later said. This was only corrected in 2000, when Eaton, working now with John Speth and Loren Cordain, published a revised analysis of hunter-gatherer diets. This new analysis took into account, as Eaton and Konner’s hadn’t, the observation that hunter-gatherers consumed the entire carcass of an animal, not just the muscle meat, and preferentially consumed the fattest parts of the carcass— including organs, tongue, and marrow— and the fattest animals. Reversing the earlier conclusion, Eaton, Speth, and Cordain now suggested that Paleolithic diets were extremely high in protein (19– 35 percent of calories), low in carbohydrates “by normal Western standards” (22– 40 percent of energy), and comparable or higher in fat (28– 58 percent of energy). Eaton and his new collaborators stated with certainty that those relatively modern foods that today constitute more than 60 percent of all calories in the typical American diet— cereal grains, dairy products, beverages, vegetable oils and dressings, and sugar and candy—“ would have contributed virtually none of the energy in the typical hunter-gatherer diet.” This latest analysis makes it seem that what Rose and the public-health authorities considered biological normality in 1985— a relatively low-fat diet— would now have to be be considered abnormal.* 22      (Kindle locations 1670-1698)
Notations:  “made a mistake”: Interview, Boyd Eaton. Revised analysis: Cordain et al. 2000 (“ would have contributed…,” 690). Paleolithic diets high in protein: Interviews, Loren Cordain, Melvin Konner, John Speth, Craig Stanford. See also Abrams 1987; Harris 1985; Stanford 2001; Stefansson 1946. (Kindle Locations 9597-9599) 
*22 Melvin Konner has doubts about the conclusions. “Boyd and I probably did underestimate the amount of meat in the Paleolithic diet based on our extrapolations for hunter-gatherers,” he said. “I just don’t think it’s nearly as extreme as this paper claims.”   (Kindle locations 13259-13261)
I have long taken issue with Taubes' referencing ways.   His book has numbered footnotes and then other notations, and then a list of references that aren't cited by number throughout the book.  It appears he interviewed a number of these people, but one wonders how long the interview was, if there are any transcriptions of these that he could even make available if asked, and how particular he was with his cherry picking.  Footnote *22 there is unclear to me, it sounds as if Konner could have been talking about the 2000 paper -- an "outlier" to be sure -- to indicate that their underestimation of meat consumption wasn't nearly as extreme as that paper claimed (to arrive at a 58% ceiling on fat).  It is also unclear when Taubes conducted these interviews.  The 2000 and 2002 papers are less clear on fats, and that range of intake varied widely, but mostly with latitude.  This is a sticking point, because if we believe that the cradle of humanity is in East Africa, then the diets of the existing northern hunter gatherers are of little consequence.  S. Boyd Eaton gave this talk in mid 2005, so it is difficult to believe that he would have implied to Taubes that paleo was high fat in an interview, even if that interview were conducted a year or two earlier.  Taubes has discussed hiring students to track down papers and such for GCBC, so there really is no excuse, whatever Eaton (or Konner, etc.) may have said in an interview, for the conflict between what is written in GCBC and a paper published in a peer review journal by a cited source in early 2006.

I don't think anything in the 2000 Cordain paper justifies Taubes' conclusion that a low fat diet would be "abnormal".  Quite the contrary, as what is defined as low fat in Western terms is around 30%, whereas the range for paleolithic humans has repeatedly been expressed as between 20-35% by the researchers he cites.

So in response to Julianna's comment, I would agree.  Yes, it is interesting how one author refutes another -- based on the same sources!  Now, there may be anthropologists out there that believe humans evolved on a largely carnivorous diet that was high in fat, but not Taubes' sources.    It really wouldn't be the first time Taubes has been accused of taking interviewees out of context in his works.


Myron Schwarzennecker said...

Yet the billionaire with the Enron background gave money to Taubes.

Has everybody seen this one:

"The New Science of Giving" What a joke. Carbsane, the guy claims he interviewed critics of Taubes before forking over the Enron money to him.

Myron Schwarzennecker said...

Maybe I shouldn't post this.

charles grashow said...

"We do not recommend consuming a high-SFA diet because SFA down-regulates the low-density lipoprotein receptor,14 thereby elevating total plasma cholesterol and low-density lipoprotein cholesterol concentrations even in normal-weight individuals. Numerous epidemiological studies have shown that elevated plasma cholesterol concentrations increase the risk for coronary heart disease.15,16. A necessary caveat to this statement is that dietary SFAs elicit this effect only under chronic hypercaloric or eucaloric conditions.17 Recent clinical trials of high-SFA diets such as the Atkins diet18-20 have proved them to be effective in improving the blood lipid profile on a short-term basis (<1 year); however, these beneficial blood lipid changes occurred only under hypocaloric conditions."

MichaelGWS said...

CarbSane/Evelyn - Been reading your blog and I do enjoy it. I'm a sucker for controversy and you're incredibly thorough in your takedowns.

But of all the big bad things out in the world - are Gary Taubes, Robb Wolf, Chris Kresser etc. really the problem?

My aging Dad in poor health is out on Natural News reading about "1 Weird Fruit that KILLS Diabetes" and my young nephew is getting sucked way too far into body building scams that promise him to "burn fat and build muscle" (at the same time??).

Personally- I'd be relived if they gave up all this crazed stuff - and blindly followed Taubes into LCHF land. I'd rather be lectured on lectins in legumes than hear someone say they're going to by the latest diet pill on Dr. Oz.

No it's not ideal. And yes, carbs are awesome (just had pasta for dinner ) but whatever. Don't let good be the enemy of perfect...or nemesis of awesome...or whatever.

Anyway - keep up the good blogging :-)

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