The Huffington Post, Meredith Melnick (@MeredithCM), the Health Director for the publication, recently informed the readers of a paper published in December 2014’s issue of The Quarterly Review of Biology, a review paper examining the evolution of human diet.1 “Paleoanthropologists are pretty amused by the faddish Paleo Diet,” said Melnick. “And now a review of studies on hominid evolution is using environmental and chemical evidence to prove, once and for all, that there was no such thing as “clean eating” during the Stone Age.” What “clean eating” actually refers to is unclear; however, Melnick believes that the Paleo diet, as we know it today, has been shown to be an inaccurate representation of what our early ancestors ate. Unfortunately, as is common from those critical of today’s Paleo diet, her biased position is founded upon little research of her own, and it appears she didn’t even read the actual paper by Sayers and Lovejoy. Had she done so, she would realize the gross misrepresentation of the words “once and for all”; for example, the very first words of the paper are “Anthropologists rarely agree on anything.” Further, throughout the paper the authors acknowledge disagreements within the literature on a number of issues as well as referencing a significant body of research that actually supports the modern Paleo diet. So, instead of reporting on the actual paper, Melnick represents her own conclusions based upon an article about the paper posted by Georgia State University (GSU) news, the academic home of the lead author. The GSU article is based more on an interview with lead author, Ken Sayers, rather than the paper itself where the peer review process is not in place and; therefore, allows the author greater freedom in expressing opinions versus the actual research on record. Consequently, the GSU article exposes some misrepresentations about the modern Paleo diet, not included in the published paper, presumably put forth by Ken Sayers. The article offers five “points that need to be considered by people wishing to emulate the diets of our ancestors.” In every case, the points made, which have been previously addressed by Paleo diet researchers, particularly at this website, offer nothing new to the debate. You can read these five points for yourself and if it is not obvious to you the responses to these misrepresentations, you can see my rebuttal to Christina Warinner’s TED lecture that made virtually the exact same misrepresentations. In regard to “Early humans (having) shorter life spans”, I addressed this common incorrect assumption in a recent blog.
What about the paper itself? The summary statement in the abstract reads as follows: “We argue that early hominid diet can best be elucidated by consideration of their entire habitat-specific resource base, and by quantifying the potential profitability and abundance of likely available foods.”
This statement, in and of itself, suggests that Paleo diet researchers have not taken this approach, which, I am confident would be argued against by those researching and publishing about Paleolithic nutrition. As with most review papers, it is a lengthy piece of work addressing the many methodologies that have been used to assess the diets of our early ancestors along with arguments for and against foods likely comprising early hominid diets. In particular, the paper states, “This review, while not ignoring the value (and limitations) of such technologies, takes a very different tack. We argue that dietary reconstruction—or, more properly, the reconstruction of foraging strategies— should strive to be holistic, and should not be limited to any one, or even several, analytical technologies. It should instead be rooted first and foremost in evolutionary ecology.” Accordingly, the authors do not appear to realize that the research that supports the modern Paleo diet has done just this. Moreover, the paper does not address the research examining the health benefits and pitfalls of the foods available to us today, as it makes sense that the foods that are better for us constituted the foods that we evolved eating.
Ultimately, however, the paper states what is supported by, and accounted for, by Paleolithic diet proponents and researchers, and what is perhaps even obvious. That is, that the diets of early hominids would have been varied and that humans were not about selecting optimal nutrition, rather, obtaining calories to survive and procreate. This tenant is well recognized2 by Paleo diet researchers and the template that makes up the modern Paleolithic diet is more about eliminating the foods NOT part of early hominid diets, rather than an exact prescription of the foods that would have been available pre the agricultural revolution. Thus, the paper does not provide a supported argument for the regular consumption of “non-Paleo Diet” plant foods such as grains and legumes, which the Paleo diet argues for elimination, or that the template of lean animal protein, vegetables, fruits, nuts and seeds would have NOT provided the staple for the early human diet.
Throughout the paper, research is referenced that makes a case for the regular consumption of underground storage organs (USOs). But, the statement “the importance of underground storage organs is currently being stressed by a vocal minority,” clearly shows this is not an agreed-upon position in the anthropological community (and certainly, not a “once for all,” as put forth by Melnick/Huffington Post). While alluding to, the paper does not directly address the fact that most USOs, like grains and legumes, cannot be consumed without being cooked and; consequently, could not have been a significant component of the early hominid diet prior to widespread use of fire. Dr. Cordain has written about this in a previous blog; but, in summary, the archaeological record from Europe does not show evidence for fire control until about 300,000 to 400,000 years ago,3,4,5 which is also far different than the ability to produce it. Habitual fire production did not occur until 75,000 to 100,000 years ago 5,6,7 which represents a very short period of time (5%) since our genus (Homo) first appeared about 2 million years ago. In turn, plant foods that required the production of fire and cooking for their digestion and assimilation would not have been part of our regular diet. Consequently, the paper’s statement “the cooking of USOs and other plant foods facilitated the cranial expansion, stature increases, and postcanine reduction observed in Homo erectus,” is at odds with the fact that habitual fire production occurred after the most recent fossil evidence of the existence of Homo erectus.8 In fact, the paper appears to be internally at odds, stating “There is also essentially no evidence of controlled use of fire or cooking in Australopithecus or earlier hominids.” Further evidence that supports that USOs were not a significant component of early hominid diets, is the finding that the salivary amylase gene (AMY1) has been shown to be a recent addition to the Homo genus.9 Consequently, “if earlier hominins were consuming large quantities of starch-rich underground storage organs, as previously hypothesized, then they were likely doing so without the digestive benefits of increased salivary amylase production.”9
The paper also recognizes that “By the time one gets to roughly 2.6 million years ago, the assertions about meat-eating in early hominids (likely Australopithecus garhi and/or early Homo) are no longer equivocal. Here there is direct evidence of modified stone tools that were used to butcher large animals and extract bone.10,11,12 The questions at this point have traditionally shifted to whether these animals were acquired by hunting or some form of scavenging, and what the importance of meat was relative to another (e.g., USOs) category of food.” So, again, a significant statement that would support the modern Paleo diet template, and as already discussed, the paper does not provide a logical case for the consumption of USOs as a significant food source.
The paper further discusses carbon enamel isotope analysis, which has had recent attention for its misinterpretation of data.13 However, in this paper, the authors actually do recognize what Fontes-Villalba et al. criticized about many of the misinterpretations13 and stated that, “this technique cannot be used alone to distinguish between plant and animal consumption.”
Another statement contained in the paper that warrants attention is “although much work remains to be done on the physiology of digestion in uncooked (and cooked) foods.” since this is an incredibly important component of Paleo diet researchers in supporting the template that makes up the modern Paleo diet. It appears, therefore, that the authors have not read the pertinent research that supports the modern Paleo template from a clinical perspective. And the effect of the modern version of the diet on health and human disease today is; perhaps, the most important issue at hand. When Dr. Cordain introduced me to Paleolithic nutrition back in the late 1980s, the dietary template was a hypothesis that would need to be tested in modern times regardless of the accuracy of the hypothesis itself. Consequently, I find it amazing how Paleo diet critics jump all over any research that suggests early human diets may have included foods not included in the modern Paleo template, or on anything slightly divergent with it, while simultaneously ignoring the research supporting the diet, and in particular the now 19 experimental and epidemiological trials showing a benefit.14-32 While knowledge of evolution of the human diet is certainly important and can provide useful guidance to what may enhance optimal human health today, it can easily be argued that the discovery that the “Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease,”16 is far more important, and does so irrespective of any accuracy of what humans actually consumed during early human evolution. Having said that, I have always considered the hypothesis logical, given that the foods on the modern Paleo template can be consumed without processing, whereas, the foods off the menu for the Paleo diet, need processing before their consumption. Further, as has been frequently pointed out, it has been shown that incorporation of these non Paleo foods into contemporary diets is now known to reduce the nutrient density (vitamins and minerals of the 13 nutrients most lacking in the US diet)33, 34 while simultaneously promoting chronic diseases of western civilization.34, 35
Ultimately, this review paper, while comprehensive, does not negate the research that supports the current modern Paleo Diet template, and the authors are either clearly unaware of, or have simply chosen to ignore the research supporting it.
Dr. Mark J. Smith graduated from Loughborough University of Technology, England, with a Bachelor of Science in PE & Sports Science and then obtained his teaching certificate in PE & Mathematics. As a top-level rugby player, he then moved to the United States and played for the Boston Rugby Club while searching the American college system for an opportunity to commence his Master’s degree. That search led him to Colorado State University where Dr. Smith completed his Masters degree in Exercise and Sport Science, with a specialization in Exercise Physiology. He continued his studies in the Department of Physiology, where he obtained his Doctorate. His research focused on the prevention of atherosclerosis (the build up of plaque in arteries that leads to cardiovascular disease); in particular, using low-dose aspirin and antioxidant supplementation. Read more…
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9. Bouri and Gona, Ethiopia
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20. Carter P1, Achana F, Troughton J, Gray LJ, Khunti K, Davies MJ. A Mediterranean diet improves HbA1c but not fasting blood glucose compared to alternative dietary strategies: a network meta-analysis. J Hum Nutr Diet. 2014 Jun;27(3):280-97
21. Jönsson T, Granfeldt Y, Lindeberg S, Hallberg AC.Subjective satiety and other experiences of a Paleolithic diet compared to a diabetes diet in patients with type 2 diabetes. Nutr J. 2013 Jul 29;12:105. doi: 10.1186/1475-2891-12-105.
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25. Bisht B, Darling WG, Grossmann RE, Shivapour ET, Lutgendorf SK, Snetselaar LG, Hall MJ, Zimmerman MB, Wahls TL. A multimodal intervention for patients with secondary progressive multiple sclerosis: Feasibility and effect on fatigue. J Altern Complement Med. 2014 Jan 29. [Epub ahead of print]
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