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Evolution and High Protein Diets Part 2 | The Paleo Diet

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THE EVOLUTIONARY EVIDENCE

The Fossil Evidence

A number of lines of evidence suggest that meat eating and high protein diets have been a component of human nutrition since the very origins of our genus Homo. Beginning approximately 2.6 million years ago (MYA), the hominin species that eventually led to Homo began to include more animal food in their diet. A number of lines of evidence support this viewpoint.

First, the very first stone tools (Oldowan lithic technology) appear in the fossil record 2.6 MYA, 28 and there is clear cut evidence to show that these tools were used to butcher and disarticulate animal carcasses. 29, 30 Stone tool cut marks on the bones of prey animals and evidence for marrow extraction appear concurrently in the fossil record with the development of Oldowan lithic technology by at least 2.5 MYA (Figure 2). 30 It is not entirely clear which specific early hominin species or group of species manufactured and used these earliest of stone tools; however, Australopithecus garhi may have been a likely candidate. 30, 31

The development of stone tools and the increased dietary reliance on animal foods allowed early African hominins to colonize northern latitudes outside of Africa where plant foods would have been seasonally restricted. Early Homo skeletal remains and Oldowan lithic technology appear at the Dmanisi site in the Republic of Georgia (40° N) by 1.75 MYA, 32 and more recently Oldowan tools dating to 1.66 MYA have been discovered at the Majuangou site in North China (40° N). 33 Both of these tool-producing hominins would likely have consumed considerably more animal food than pre-lithic hominins living in more temperate African climates, and it is likely the majority of their daily energy was obtained from animal foods during winter and early spring when plant food sources would have been scarce or unavailable.

The Genetic Evidence

In addition to the fossil evidence suggesting a trend for increased animal food consumption, hominins may have experienced a number of genetic adaptations to animal-based diets early in our genus’s evolution analogous to those of obligate carnivores such as felines. Carnivorous diets reduce evolutionary selective pressures that act to maintain certain anatomical and physiological characteristics needed to process and metabolize high amounts of plant foods. In this regard, hominins, like felines, have experienced a reduction in gut size and metabolic activity along with a concurrent expansion of brain size and metabolic activity as they included more energetically dense animal food into their diets. 16, 34, 35

Further, similar to obligate carnivores, 36 humans maintain an inefficient ability to chain elongate and desaturate 18 carbon fatty acids to their product 20 and 22 carbon fatty acids. 37 Since 20 and 22 carbon fatty acids are essential cellular lipids, then evolutionary reductions in desaturase and elongase activity in hominins indicate that preformed dietary 20 and 22 carbon fatty acids (found only in animal foods) were increasingly incorporated in lieu of their endogenously synthesized counterparts derived from 18 carbon plant fatty acids.

Finally, our species has a limited ability to synthesize the biologically important amino acid, taurine, from precursor amino acids, 38, 39 and vegetarian diets in humans result in lowered plasma and urinary concentrations of taurine. 40 Like felines 41, 42 the need to endogenously synthesize taurine may have been evolutionarily reduced in humans because exogenous dietary sources of preformed taurine (found only in animal food) had relaxed the selective pressure formerly requiring the need to synthesize this conditionally essential amino acid.

Another genetic adaptation to a high meat diet involves the metabolism of purines.  Purines are the nitrogenous base pairs which form the structural cross rung molecules of both DNA and RNA.  As DNA and RNA are broken down within cells, the purines then can be metabolized into uric acid by the liver and a few other tissues within the body.  The liver receives purines from two sources: 1) the diet, and 2) the daily breakdown of the body’s own tissues. About ⅔ of the daily purine load comes from the body’s turnover of cells, while ⅓ comes from the diet. 43 When the combined purine load (from both diet and turnover of the body’s own cells) exceeds the kidney’s ability to excrete it, blood concentrations of uric acid rise, thereby increasing the risk for gout, a painful disease caused by formation of uric acid crystals in the joints.

Although high protein, meat based diets contain high amounts of purines and would be expected to promote gout symptoms, protein ingestion actually decreases blood uric acid levels by increasing uric acid excretion. 44 This seemingly paradoxical effect occurs because the kidney increases its excretion of uric acid when faced with elevated dietary purines. 45 But more importantly, over the course of evolution, humans have evolved a genetic mutation which tends to prevent uric acid synthesis in the liver. Humans avoid the overproduction of uric acid in the face of increasing dietary purine intake from meats by decreasing the activity of an enzyme called xanthine oxidoreductase, 46 a key catalyst in the final synthesis of uric acid. Compared to other animals, xanthine oxidase activity is almost 100 times lower in humans. 47 This evolutionary adaptation has occurred because the gene coding for xanthine oxidoreductase has been repressed. 48 The final proof of the pudding has been borne out by dietary interventions showing that high protein, low glycemic load diets actually normalized serum uric acid concentrations in 7 of 12 gout patients and significantly decreased gout attacks. 49

The Isotopic Fossil Evidence

Since the evolutionary split between hominins and pongids (apes) approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant and animal foods. In support of this view is the omnivorous nature of chimpanzees, the closest living pongid link to hominins. Although chimpanzees (Pan paniscus and Pan troglodytes), our genetically closest nonhuman relatives, primarily consume a frugivorous diet, they still eat a substantial amount of meat obtained throughout the year from hunting and scavenging. 50-52 Observational studies of wild chimpanzees demonstrate that during the dry season meat intake is about 65g per day for adults. 51 Accordingly, it is likely that the very earliest hominins would have been capable of obtaining animal food through hunting and scavenging in a manner similar to chimpanzees.

Carbon isotope data also support the notion that early hominins were omnivorous. By about 3 million years ago MYA Australopithecus africanus obtained a significant portion of food from C4 sources (grasses, particularly seeds and rhizomes; sedges; invertebrates, including locusts and termites; grazing mammals; and perhaps even insectivores and carnivores). 53 Other fossils of early African hominins, including Australopithecus robustus and Homo ergaster, maintain carbon isotope signatures characteristic of omnivores. 54, 55 The finding of C4 in Australopithecus robustus fossils refutes the earlier view that this hominin was vegetarian. 54

There is little evidence to the contrary that animal foods have always played a significant role in the diets of all hominin species. Increased reliance on animal foods not only allowed for enhanced encephalization (brain expansion relative to body weight) and its concomitant behavioral sophistication, 16, 34, 35 but this dietary practice also permitted colonization of the world outside of Africa. An unresolved issue surrounding hominin diets is the relative amounts of plant and animal foods that were typically consumed.

Before the advent of Oldowan lithic technology about 2.6 MYA, quantitative estimates of hominin energy intake from animal food sources are unclear, other than they were likely similar to, or greater than, estimated values (4%–8.5% total energy) for chimpanzees. 51, 56 Although all available data point to increasing animal food consumption following the arrival of stone tool technology, the precise contribution of either animal or plant food energy to is unclear. Obviously, then as now, no single (animal/plant) subsistence ratio would have been necessarily representative of all populations or species of hominins. However, there are a number of lines of evidence which suggest more than half (>50%) of the average daily energy intake for most Paleolithic hominin species and populations of species was obtained from animal foods.

Richards, Pettitt, and colleagues 57 have examined stable isotopes (δ13C and δ15N) in two Neanderthal specimens (~28,000—29,000 years ago) from Vindija Cave in northern Croatia and contrasted these isotopic signatures to those in fossils of herbivorous and carnivorous mammals from the same ecosystem. The analysis demonstrated that Neanderthals, similar to wolves and arctic foxes, behaved as top-level carnivores, obtaining all of their protein from animal sources. 57  More recent studies of corroborate this earlier work and points to Neanderthals “as top predators in an open environment, with little variation through time and space,58 and “the percentage of plants in the Neanderthal diet must have been close to zero.” 59 Because Neanderthals were not direct predecessors of modern humans, 60 it may be more relevant to examine the isotopic data from fully modern humans living during the Pleistocene. An analysis was made of five Upper Paleolithic Homo sapiens specimens dated to ~11,700–12,380 years ago from Gough’s and Sun Hole Caves in Britain. 61 The data indicated these hunter-gatherers were consuming animal protein year-round at a higher trophic level than the artic fox.

All of these studies 57-62 could be criticized as not being representative of typical hominin diets, as these two species lived in climates and ecosystems that fostered an abundance of large, huntable mammals, which were preyed upon preferentially. Additional clues to the typical plant-to-animal subsistence ratio in Paleolithic hominin diets can be found in the foraging practices of historically studied hunter-gatherers.

The Ethnographic Evidence

Our analysis (Figure 3) of the Ethnographic Atlas data 62 showed that the dominant foods in the majority of historically studied hunter-gatherer diets were derived from animal food sources. 14 Most (73%) of the world’s hunters-gatherers obtained >50% of their subsistence from hunted and fished animal foods, whereas only 14% of worldwide hunter-gatherers obtained >50% of their subsistence from gathered plant foods. For all 229 hunter-gatherer societies, the median subsistence dependence on animal foods was 56% to 65%. In contrast, the median subsistence dependence on gathered plant foods was 26% to 35%. 14

The major limitation of ethnographic data is that the preponderance of it is subjective in nature, and the assigned scores for the five basic subsistence economies in the Ethnographic Atlas are not precise, but rather are approximations. 63 Fortunately, more exact, quantitative dietary studies were carried out on a small percentage of the world’s hunter gatherer societies. 15, 64

Evolution and High Protein Diets Part 2 | The Paleo Diet

Figure 3. Frequency distribution of subsistence dependence upon animal foods in worldwide hunter gatherer societies (n = 229).

Table 1 lists these studies and shows the plant-to-animal subsistence ratios by energy. The average score for animal food subsistence is 65%, while that for plant-food subsistence is 35%. These values are similar to our analysis of the entire (n = 229) sample of hunter-gatherer societies listed in the Ethnographic Atlas in which the mean score for animal food subsistence was 68% and that for plant food was 32%. 14

Evolution and High Protein Diets Part 2 | The Paleo Diet

Table 1. Quantitatively determined proportions of plant and animal food in hunter-gatherer diets. 15, 64

When the two polar hunter-gatherer populations, who have no choice but to eat animal food because of the inaccessibility of plant foods, are excluded from Table 1 the mean score for animal subsistence is 59% and that for plant-food subsistence is 41%. These animal-to-plant subsistence values fall within the same respective class intervals (56%–65% for animal food; 26%–35% for plant food) as those we estimated from the ethnographic data when the confounding influence of latitude was eliminated. 14 Consequently, there is remarkably close agreement between the quantitative data in Table 1 and the ethnographic data 14 that animal food comprised more than half of the energy in historically studied hunter-gatherer diets.

Based upon hunter gatherer plant to animal subsistence ratios and the known macronutrient contents of wild plant and animal foods, it is possible to estimate the macronutrient content of these diets. 14 The typical hunter-gatherer protein intake would have fallen between 19 and 35% of total energy, 14 values which would be labeled either “high” or “very high” protein diets when compared to current U.S. values (15%).

Consequently, when framed in an evolutionary context, current western dietary protein intakes fall outside the range of diets that would have conditioned the human genome for nearly 2 million years. The evolutionary template would then suggest that when dietary protein intakes are restored to levels that our species is genetically accustomed, good health will prevail. Conversely, lower or higher values likely result in ill health.  Let’s see what the experimental evidence shows tomorrow in “Evolution and High Protein Diets Part 3” of The Evolutionary Basis for the Therapeutic Effects of High Protein Diets Series.

 

REFERENCES

Part 1 & Part 2

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[28]Semaw S, Rogers MJ, Quade J, Renne PR, Butler RF, Dominguez-Rodrigo M, Stout D, Hart WS, Pickering T, Simpson SW. 2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia. J Hum Evol. 2003 Aug;45(2):169-77.

[29]Bunn, HT, Kroll EM. Systematic butchery by Plio-Pleistocene hominids at Olduvai Gorge, Tanzania. Curr Anthropol 1986;20:365–398.

[30]de Heinzelin J, Clark JD, White T, Hart W, Renne P, WoldeGabriel G, Beyene Y, Vrba E. Environment and behavior of 2.5-million-year-old Bouri hominids. Science. 1999 Apr 23;284(5414):625-9

[31]Asfaw B. White T, Lovejoy O, Latimer B, Simpson S, Suwa, G. Australopithecus garhi: A new species of early hominid from Ethiopia. Science 1999; 284, 629–635.

[32]Vekua A, Lordkipanidze D, Rightmire GP, Agusti J, Ferring R, Maisuradze G, Mouskhelishvili A, Nioradze M, De Leon MP, Tappen M, Tvalchrelidze M, Zollikofer C. A new skull of early Homo from Dmanisi, Georgia. Science. 2002 Jul 5;297(5578):85-9.

[32]Zhu RX, Potts R, Xie F. Hoffman KA, Deng CL, Shi CD, Pan YX, Wang HQ, Shi, RP, Wang YC, Shi GH, Wu NQ. New evidence on the earliest human presence at high northern latitudes in northeast Asia. Nature 2004; 431: 559–562.

[33]Aiello LC, Wheeler P. The expensive tissue hypothesis. Curr Anthropol 1995; 36:199–222.

[34]Leonard W.R, Robertson ML. Evolutionary perspectives on human nutrition: The influence of brain and body size on diet and metabolism. Am J Hum Biol 1994; 6: 77–88.

[35]Pawlosky R., Barnes A., Salem, N. Essential fatty acid metabolism in the feline: Relationship between liver and brain production of long-chain polyunsaturated fatty acids. J Lipid Res 1994;35: 2032–2040.

[36]Hussein N, Ah-Sing E, Wilkinson P, Leach C, Griffin BA, Millward DJ. Long-chain conversion of [13C] linoleic acid and alpha-linolenic acid in response to marked changes in their dietary intake in men. J Lipid Res. 2005 Feb;46(2):269-80.

[37]Sturman JA, Hepner GW, Hofmann AF, Thomas PJ. Metabolism of [35S] taurine in man. J Nutr. 1975 Sep;105(9):1206-14.

[38]Chesney RW, Helms RA, Christensen M, Budreau AM, Han X, Sturman JA. The role of taurine in infant nutrition. Adv Exp Med Biol. 1998;442:463-76.

[39]Laidlaw SA, Shultz TD, Cecchino JT, Kopple JD. Plasma and urine taurine levels in vegans. Am J Clin Nutr. 1988 Apr;47(4):660-3.

[40]Knopf K, Sturman JA, Armstrong M, Hayes KC. 1978. Taurine: An essential nutrient for the cat. J Nutr 1978;108: 773–778.

[41]MacDonald ML, Rogers QR, Morris JG. Nutrition of the domestic cat, a mammalian carnivore. Annu Rev Nutr 1984; 4: 521–562.

[42]Fam AG. Gout: excess calories, purines, and alcohol intake and beyond. Response to a urate-lowering diet. J Rheumatol. 2005 May;32(5):773-7.

[43]Matzkies F, Berg G, Madl H. The uricosuric action of protein in man. Adv Exp Med Biol 1980;122A:227-31.

[44]Loffler W. Grobner W, Medina R, Zollner N. Influence of dietary purines on pool size, turnover, and excretion of uric acid during balance conditions. Isotope studies using 15N-uric acid. Res Exp Med (Berl). 1982(2):113-123.

[45]Oda M, Satta Y, Takenaka O, Takahata N. Loss of urate oxidase activity in hominoids and its evolutionary implications. Mol Biol Evol. 2002 May; 19(5): 640-53.

[46]Abadeh S, Killacky J, Benboubetra M, Harrison R. Purification and partial characterization of xanthine oxidase from human milk. Biochim Biophys Acta. 1992 Jul 21;1117(1):25-32

[47]Xu P, LaVallee P, Hoidal JR. Repressed expression of the human xanthine oxidoreductase gene. E-box and TATA-like elements restrict ground state transcriptional activity. J Biol Chem. 2000 Feb 25;275(8):5918-26.

[48]Dessein PH, Shipton EA, Stanwix AE, Joffe BI, Ramokgadi J. Beneficial effects of weight loss associated with moderate calorie/carbohydrate restriction, and increased proportional intake of protein and unsaturated fat on serum urate and lipoprotein levels in gout: a pilot study. Ann Rheum Dis. 2000 Jul;59(7):539-43.

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EVOLUTION AND HIGH PROTEIN DIETS PART 1

The Evolutionary Basis for the Therapeutic Effects of High Protein Diets Series

Did you miss Evolution and High Protein Diets Part 2? Click Here to Read It!

Did you miss Evolution and High Protein Diets Part 3? Click Here to Read It!

INTRODUCTION

Although humanity has been interested in diet and health for thousands of years, the organized, scientific study of nutrition has a relatively recent past.  For instance, the world’s first scientific journal devoted entirely to diet and nutrition, The Journal of Nutrition only began publication in 1928.  Other well known nutrition journals have a more recent history still: The British Journal of Nutrition (1947), The American Journal of Clinical Nutrition (1954), and The European Journal of Clinical Nutrition (1988).   The first vitamin was “discovered” in 1912 and the last vitamin (B12) was identified in 1948.1 The scientific notion that omega 3 fatty acids have beneficial health effects dates back only to the late 1970’s,2 and the characterization of the glycemic index of foods only began in 1981.3

Nutritional science is not only a newly established discipline, but it is also a highly fractionated, contentious field with constantly changing viewpoints on both major and minor issues that impact public health.  For example, in 1996 a task force of experts from the American Society for Clinical Nutrition (ASCN) and the American Institute of Nutrition (AIN) came out with an official position paper on trans fatty acids stating:

We cannot conclude that the intake of trans fatty acids is a risk factor for coronary heart disease.4

Fast forward six short years to 2002 and the National Academy of Sciences, Institute of Medicine’s report on trans fatty acids5 states:

Because there is a positive linear trend between trans fatty acid intake and total and LDL (“bad”) cholesterol concentration, and therefore increased risk of cardiovascular heart disease, the Food and Nutrition Board recommends that trans fatty acid consumption be as low as possible while consuming a nutritionally adequate diet.”

These kinds of complete turnabouts and divergence of opinion regarding diet and health are commonplace in the scientific, governmental and medical communities. The official U.S. governmental recommendations for healthy eating are outlined in the “My Pyramid” program6 which replaced the “Food Pyramid” – both of which have been loudly condemned for nutritional shortcomings by scientists from the Harvard School of Public Health.7 Dietary advice by the American Heart Association (AHA) to reduce the risk of coronary heart disease (CHD) is to limit total fat intake to 30% of total energy, to limit saturated fat to <10% of energy and cholesterol to <300 mg/day while eating at least 2 servings of fish per week.8

Although similar recommendations are proffered in the USDA “My Pyramid,” weekly fish consumption is not recommended because the authors of these guidelines feel there is only “limited” information regarding the role of omega 3 fatty acids in preventing cardiovascular disease.6 Surprisingly, the personnel makeup of both scientific advisory boards is almost identical. At least 30 million Americans have followed Dr. Atkins advice to eat more fat and meat to lose weight.9 In utter contrast, Dean Ornish tells us fat and meat cause cancer, heart disease and obesity, and that we would all would be a lot healthier if we were strict vegetarians.10 Who’s right and who’s wrong?  How in the world can anyone make any sense out of this apparent disarray of conflicting facts, opinions and ideas?

In mature and well-developed scientific disciplines there are universal paradigms that guide scientists to fruitful end points as they design their experiments and hypotheses.  For instance, in cosmology (the study of the universe) the guiding paradigm is the “Big Bang” concept showing that the universe began with an enormous explosion and has been expanding ever since. In geology, the “Continental Drift” model established that all of the current continents at one time formed a continuous landmass that eventually drifted apart to form the present-day continents. These central concepts are not theories for each discipline, but rather are indisputable facts that serve as orientation points for all other inquiry within each discipline. Scientists do not know everything about the nature of universe, but it absolutely unquestionable that it has been and is expanding. This central knowledge then serves as a guiding template which allows scientists to make much more accurate and informed hypotheses about factors yet to be discovered.

The study of human nutrition remains an immature science because it lacks a universally acknowledged unifying paradigm.11 Without an overarching and guiding template, it is not surprising that there is such seeming chaos, disagreement and confusion in the discipline. The renowned Ukrainian geneticist Theodosius Dobzhansky (1900-1975) said, “Nothing in biology makes sense except in the light of evolution.12 Indeed, nothing in nutrition seems to make sense because most nutritionists have little or no formal training in evolutionary theory, much less human evolution. Nutritionists face the same problem anyone who is not using an evolutionary model to evaluate biology: fragmented information and no coherent way to interpret the data.

All human nutritional requirements like those of all living organisms are ultimately genetically determined.  Most nutritionists are aware of this basic concept; what they have little appreciation for is the process (natural selection) which uniquely shaped our species nutritional requirements. By carefully examining the ancient environment under which our genome arose, it is possible to gain insight into our present day nutritional requirements and the range of foods and diets to which we are genetically adapted via natural selection.13-16 This insight can then be employed as a template to organize and make sense out of experimental and epidemiological studies of human biology and nutrition.11

THE DIETARY PROTEIN CONUNDRUM: HOW MUCH IS ENOUGH?

An important dietary issue that has come under debate in recent years is the safety of high protein diets and their long term influence upon health and well being.17, 18 In the current U.S. diet the average protein intake is 98.6 g/day (15.5% of total energy) for men and 67.5 g/day (15.1% of total energy) for women.19 Animal products provide approximately 75% of the protein in the U.S. food supply followed by dairy, cereals, eggs, legumes, fruits and vegetables.20 Diets containing  20% or more of their total energy as protein have been labeled “high protein diets” and those containing 30% or more energy as protein have been dubbed “very high protein diets.”18 Accordingly, a “high protein diet” for the average U.S. male daily energy intake (2,618 kcal)19 would contain between 125 to 186 grams of protein per day and for the average female (1,877 kcal)19 between 89 to 133 grams of protein per day.

At this point, it should be noted that there is a physiological limit to the amount of protein that can be ingested before it becomes toxic.14, 21 A byproduct of dietary protein metabolism is nitrogen, which in turn is converted into urea by the liver and then excreted by the kidneys into the urine. The upper limit of protein ingestion is determined by the liver’s ability to synthesize urea. When nitrogen intake from dietary protein exceeds the ability of the liver to synthesize urea, excessive nitrogen (as ammonia) spills into the bloodstream causing hyperammonemia and toxicity.14, 21 Additionally excess amino acids from the metabolism of high amounts of dietary protein may become toxic by entering the circulation causing hyperaminoacidemia.14, 21

The avoidance of the physiological effects of protein excess has been an important factor in shaping the subsistence strategies of hunter-gatherers.22- 24 Multiple historical and ethnographic accounts have documented the deleterious health effects that have occurred when humans were forced to rely solely upon the fat depleted, lean meat of wild animals.22  Excess consumption of dietary protein from the lean meats of wild animals leads to a condition referred to by early American explorers as “rabbit starvation” which initially results in nausea, then diarrhea and eventual death.22 Clinical documentation of this syndrome is virtually non-existent, except for a single case study.25

Using known maximal rates of urea synthesis (MRUS) in normal subjects [65 mg N/h ×  kg (body weight )0.75] (range 55-76), it is possible to calculate the maximal protein intake, beyond which will exceed MRUS and result in hyperammonemia and hyperaminoacidemia.21 The mean maximal protein intake for the average weight U.S. male (189.4 lbs)26 is then 270 g/day (range 233-322 g/day), and for an average weight female (162.8 lbs),26 246 g/day (range 208-288 g/day).  Consequently, “very high protein diets” for the average U.S. male could range from 187 to 270 g/day and for females, 134 to 246 g/day.

So let’s summarize a few key points. The average protein intake in the U.S. is about 15% of the normal daily caloric intake.  Diets labeled as “high protein” contain 20-29% protein of the normal daily caloric intake, and diets with 30-40% protein are branded “very high protein.” It should be pointed out that this categorization is completely arbitrary and based almost entirely upon comparisons to the U.S. norm.

A salient question from an evolutionary perspective would be, “Is the average U.S. protein intake necessarily average or normal for our species?”  For example, blood pressure in the U.S. and most other westernized countries is considered “normal” when systolic pressure is 120 mm Hg and diastolic pressure is 80 mm Hg. However, in many non-westernized people these values would be higher than normal. Consider the data in Figure 1 below showing blood pressure in the Yanomamo Indians of Brazil, a non-salt consuming society. Not only is blood pressure lower than normal western values, but it stays uniform throughout life and does not rise with age.27

Figure 1. Blood pressure in a group of 506 Brazilian Indians.26

The Evolutionary Basis for the Therapeutic Effects of High Protein Diets Series | The Paleo Diet
The Evolutionary Basis for the Therapeutic Effects of High Protein Diets Series | The Paleo Diet

In order to objectively answer the question whether or not high protein diets have detrimental or therapeutic health effects compared to the U.S. norm (15% total energy), we will frame this question from an evolutionary perspective before examining the experimental and epidemiological evidence tomorrow in “Evolution and High Protein Diets Part 2” of The Evolutionary Basis for the Therapeutic Effects of High Protein Diets Series.

 

REFERENCES

[1]. Bogert LJ, Briggs GM, Calloway DH. Nutrition and Physical Fitness, Ninth Edition. W.B. Sauders Company, Philadelphia, 1973.

[2] Dyerberg J, Bang HO. A hypothesis on the development of acute myocardial infarction in Greenlanders. Scand J Clin Lab Invest Suppl. 1982;161:7-13.

[3] Jenkins DJ, Wolever TM, Taylor RH, Barker H, Fielden H, Baldwin JM, Bowling AC, Newman HC, Jenkins AL, Goff DV. Glycemic index of foods: a physiological basis for carbohydrate exchange. Am J Clin Nutr. 1981 Mar;34(3):362-6.

[4] No authors listed. Position paper on trans fatty acids. ASCN/AIN Task Force on Trans Fatty Acids. American Society for Clinical Nutrition and American Institute of Nutrition. Am J Clin Nutr. 1996 May;63(5):663-70.

[5] National Academy of Sciences, Institute of Medicine. Letter Report on Dietary Reference Intakes for Trans Fatty Acids, 2002. http://www.iom.edu/CMS/5410.aspx.

[6]

[7] Willett WC, Stampfer MJ. Rebuilding the food pyramid. Sci Am. 2003 Jan;288(1):64-71

[8] Krauss RM, Eckel RH, Howard B, et al. Dietary Guidelines: revision 2000: A statement for healthcare professionals from the Nutrition Committee of the American Heart Association. Circulation. 2000 Oct 31;102(18):2284-99.

[9] Blanck HM, Gillespie C, Serdula MK, Khan LK, Galusk DA, Ainsworth BE .Use of low-carbohydrate, high-protein diets among americans: correlates, duration, and weight loss. MedGenMed. 2006 Apr 5;8(2):5.

[10] Ornish D. Dr. Dean Ornish’s Program for Reversing Heart Disease: The Only System Scientifically Proven to Reverse Heart Disease Without Drugs or Surgery. New York : Random House, 1990.

[11] Nesse RM, Stearns SC, Omenn GS. Medicine needs evolution. Science 2006;311:1071.

[12] Dobzhansky T. Am Biol Teacher. 1973 March; 35:125-129.

[13] Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, O’Keefe JH, Brand-Miller .Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr. 2005 Feb;81(2):341-54.

[4] Cordain L, Miller JB, Eaton SB, Mann N, Holt SH, Speth JD. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr. 2000 Mar;71(3):682-92.

[15] Cordain L, Eaton SB, Brand Miller J, Mann N, Hill K. The paradoxical nature of hunter-gatherer diets: Meat based, yet non-atherogenic. Eur J Clin Nutr 2002; 56 (suppl 1):S42-S52.

[16] Cordain L, Watkins BA, Mann NJ. Fatty acid composition and energy density of foods available to African hominids: evolutionary implications for human brain development. World Rev Nutr Diet 2001, 90:144-161.

[17] Bravata DM, Sanders L, Huang J, Krumholz HM, Olkin I, Gardner CD, Bravata DM. Efficacy and safety of low-carbohydrate diets: a systematic review.
JAMA. 2003 Apr 9;289(14):1837-50.

[18] St Jeor ST, Howard BV, Prewitt TE, Bovee V, Bazzarre T, Eckel RH et al.. Dietary protein and weight reduction: a statement for healthcare professionals from the Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association. Circulation. 2001 Oct 9;104(15):1869-74.

[19] Wright JD, J Kennedy-Stephenson J, Wang CY, McDowell MA, Johnson CL, National Center for Health Statistics, CDC. Trends in intake of energy and macronutrients—United States, 1971-2000. JAMA. 2004;291:1193-1194.

[20] McDowell M, Briefel R, Alaimo K, et al. Energy and macronutrient intakes of persons ages 2 months and over in the United States: Third National Health and Nutrition Examination Survey, Phase 1, 1988–91. Washington, DC: US Government Printing Office, Vital and Health Statistics; 1994. CDC publication No. 255.

[21] Rudman D, DiFulco TJ, Galambos JT, Smith RB 3rd, Salam AA, Warren WD. Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects.J Clin Invest. 1973 Sep;52(9):2241-9.

[22] peth JD, Spielmann KA. Energy source, protein metabolism, and hunter-gatherer subsistence strategies. J Anthropological Archaeology 1983;2:1-31.

[23] Speth JD. Early hominid hunting and scavenging: the role of meat as an energy source. J Hum Evol 1989;18:329-43.

[24] Noli D, Avery G. Protein poisoning and coastal subsistence. J Archaeological Sci 1988;15:395-401.

[25] Lieb CW. The effects on human beings of a twelve months’ exclusive meat diet. JAMA 1929;93:20-22.

[26] Ogden CL, Fryar CD, Carroll MD, Flegal KM. Mean body weight, height and body mass index, United States 1960—2002 . Center for Disease Control. Advance Data from Vital and Health Statistics, No. 347, October 27, 2004.

[27] Oliver WJ, Cohen EL, Neel JV. Blood pressure, sodium intake, and sodium related hormones in the Yanomamo Indians, a “no-salt” culture. Circulation. 1975 Jul;52(1):146-51.

Sprouting Truth From the Rubble: The Modern Paleo Diet Template

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.1Paleoanthropologists 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
@docmarksmith
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Dr. Mark J. Smith | The Paleo DietDr. 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…

REFERENCES

1. Sayers K, Lovejoy CO. Blood, bulbs, and bunodonts: on evolutionary ecology and the diets of Ardipithecus, Australopithecus, and early Homo.  Q Rev Biol. 2014 Dec;89(4):319-57.

2. Cordain L, Miller JB, Eaton SB, Mann N, Holt SH, Speth JD. Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. Am J Clin Nutr. 2000 Mar;71(3):682-92.

3. James, SR. Hominid use of fire in the Lower and Middle Pleistocene: a review of the evidence. Curr Anthropol 1989;30: 1-26.

4. Sorensen A, Roebroeks W, van Gijn A. Fire production in the deep past? The expedient strike-a-light model. J Archaeol Sci 2014; 42:476-486.

5. Sandgathe DM, Dibble HL, Goldberg P, McPherron SP, Turq A, Niven L, Hodgkins J. Timing of the appearance of habitual fire use. Proc Natl Acad Sci U S A. 2011 Jul 19;108(29):E298.

6. Sandgathe DM, Dibble HL, Goldberg P, McPherron SP, Turq A, Niven L, Hodgkins J. On the role of fire in Neandertal adaptations in western Europe: evidence from Pech de l’Aze IV and Roc de Marsal, France. Paleo Anthropology 2011;216-242.

7. Maslin MA, Shultz S, Trauth MH. 2015 A synthesis of the theories and concepts of early human evolution. Phil. Trans. R. Soc. B 370: 20140064. http://dx.doi.org/10.1098/rstb.2014.0064.

8. Perry GH, Kistler L, Kelaita MA, Sams AJ. Insights into hominin phenotypic and dietary evolution from ancient DNA sequence data. J Hum Evol. 2015 Jan 3. pii: S0047-2484(14)00264-4. doi: 10.1016/j.jhevol.2014.10.018. [Epub ahead of print]

9. Bouri and Gona, Ethiopia

10. Heinzelin J., Clark J. D., White T., Hart W., Renne P., WoldeGabriel G., Beyene Y., Vrba E. 1999. Environment and behavior of 2.5-million-year-old Bouri hominids. Science 284:625–629.

11. Semaw S., Rogers M. J., Quade J., Renne P. R., Butler R. F., Domı´nguez-Rodrigo M., Stout D., Hart W. S., Pickering T., Simpson S. W. 2003. 2.6-million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia. Journal of Human Evolution 45:169 –177.

12. Fontes-Villalba M, Carrera-Bastos P, Cordain L. African hominin stable isotopic data do not necessarily indicate grass consumption. Proc Natl Acad Sci U S A. 2013 Oct 22;110(43):E4055.

13. O’Dea K: Marked improvement in carbohydrate and lipid metabolism in diabetic Australian aborigines after temporary reversion to traditional lifestyle. Diabetes 1984, 33(6):596-603.

14. Jonsson T, Ahren B, Pacini G, Sundler F, Wierup N, Steen S, Sjoberg T, Ugander M, Frostegard J, Goransson Lindeberg S: A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein and lower blood pressure than a cereal-based diet in domestic pigs. Nutr Metab (Lond) 2006, 3:39.

15. Lindeberg S, Jonsson T, Granfeldt Y, Borgstrand E, Soffman J, Sjostrom K, Ahren B: A Palaeolithic diet improves glucose tolerance more than a Mediterranean-like diet in individuals with ischaemic heart disease. Diabetologia 2007, 50(9):1795-1807.

16. Osterdahl M, Kocturk T, Koochek A, Wandell PE: Effects of a short-term intervention with a paleolithic diet in healthy volunteers. Eur J Clin Nutr 2008, 62(5):682-685.

17. Jönsson T, Granfeldt Y, Ahrén B, Branell UC, Pålsson G, Hansson A, Söderström M, Lindeberg S. Beneficial effects of a Paleolithic diet on cardiovascular risk factors in type 2 diabetes: a randomized cross-over pilot study. Cardiovasc Diabetol. 2009;8:35

18. Frassetto LA, Schloetter M, Mietus-Synder M, Morris RC, Jr., Sebastian A: Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr 2009.

19. Jonsson T, Granfeldt Y, Erlanson-Albertsson C, Ahren B, Lindeberg S. A Paleolithic diet is more satiating per calorie than a Mediterranean-like diet in individuals with ischemic heart disease. Nutr Metab (Lond). 2010 Nov 30;7(1):85

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.

22. Ryberg M, Sandberg S, Mellberg C, Stegle O, Lindahl B, Larsson C, Hauksson J, Olsson T. A Palaeolithic-type diet causes strong tissue-specific effects on ectopic fat deposition in obese postmenopausal women. J Intern Med. 2013 Jul;274(1):67-76

23. Frassetto LA, Shi L, Schloetter M, Sebastian A, Remer T. Established dietary estimates of net acid production do not predict measured net acid excretion in patients with Type 2 diabetes on Paleolithic-Hunter-Gatherer-type diets. Eur J Clin Nutr. 2013 Sep;67(9):899-903

24. Fontes-Villalba M, Jönsson T, Granfeldt Y, Frassetto LA, Sundquist J, Sundquist K, Carrera-Bastos P, Fika-Hernándo M, Picazo Ó, Lindeberg S. A healthy diet with and without cereal grains and dairy products in patients with type 2 diabetes: study protocol for a random-order cross-over pilot study–Alimentation and Diabetes in Lanzarote–ADILAN.Trials. 2014 Jan 2;15:2. doi: 10.1186/1745-6215-15-2.

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]

26. Mellberg C, Sandberg S, Ryberg M, Eriksson M, Brage S, Larsson C, Olsson T, Lindahl B. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. Eur J Clin Nutr. 2014 Mar;68(3):350-7.

27. Smith, M, Trexler E, Sommer A, Starkoff B, Devor S.teven (2014) Unrestricted Paleolithic Diet is associated with unfavorable changes to blood lipids in healthy subjects. Int J Exer Sci 2014, 7(2) : 128-139.

28. Talreja D, Buchanan H, Talreja R, Heiby L, Thomas B, Wetmore J, Pourfarzib R, Winegar D. Impact of a Paleolithic diet on modifiable CV risk factors. Journal of Clinical Lipidology, Volume 8, Issue3, Page 341, May 2014.

29. Boers I, Muskiet FA, Berkelaar E, Schur E, Penders R, Hoenderdos K, Wichers HJ, Jong MC. Favourable effects of consuming a Palaeolithic-type diet on characteristics of the metabolic syndrom. A randomized controlled pilot-study. Lipids Health Dis. 2014 Oct 11;13:160. doi: 10.1186/1476-511X-13-160.

30. Stomby A, Simonyte K, Mellberg C, Ryberg M, Stimson RH, Larsson C, Lindahl B, Andrew R, Walker BR, Olsson T. Diet-induced weight loss has chronic tissue-specific effects on glucocorticoid metabolism in overweight postmenopausal women. Int J Obes (Lond). 2014 Oct 28. doi: 10.1038/ijo.2014.188. [Epub ahead of print]

31. Whalen KA, McCullough M, Flanders WD, Hartman TJ, Judd S, Bostick RM. Paleolithic and mediterranean diet pattern scores and risk of incident, sporadic colorectal adenomas. Am J Epidemiol. 2014 Dec 1;180(11):1088-97. doi: 10.1093/aje/kwu235. Epub 2014 Oct 17.

32. Cordain L. The nutritional characteristics of a contemporary diet based upon Paleolithic food groups. J Am Neutraceut Assoc 2002; 5:15-24.

33. Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, O’Keefe JH, Brand-Miller J. Origins and evolution of the western diet: Health implications for the 21st century. Am J Clin Nutr 2005;81:341-54.

34. Carrera-Bastos P, Fontes Villalba M, O’Keefe JH, Lindeberg S, Cordain L. The western diet and lifestyle and diseases of civilization. Res Rep Clin Cardiol 2011; 2: 215-235.

35. Ibid.

Physical activity, sleep, sun exposure and dietary needs of every living organism (including humans) are genetically determined. In this regard, despite the occurrence of important genetic changes since the Agricultural Revolution, most of the human genome is comprised of genes selected during the Paleolithic Era, a period that lasted from about 2.5 million to 11,000 years ago.

Moreover, hunter-gatherers, and other populations minimally affected by modern habits, when compared to industrialized populations, exhibit superior health markers, body composition and physical fitness and a very low incidence of chronic degenerative diseases.

As such, we recognize the profound changes in diet and lifestyle that occurred after the Neolithic Revolution – and more so after the Industrial Revolution and the Modern Age – are too recent on an evolutionary time scale for the human genome to have fully adapted.

This means that in order to achieve our normal (optimal) phenotype, it is important to mimic the ancestral environment, as pictured in the Normal Phenotype figure below.

Human Genome Normal Phenotype| The Paleo Diet

Because we are not genetically adapted to the modern environment, when exposed to that environment virtually everyone will experience a suboptimal phenotype, pictured below. A suboptimal phenotype may or may not be considered pathological, depending on genetic and epigenetic variants.

Human Genome Suboptimal Phenotype | The Paleo Diet

Learn more “The Western Diet and Lifestyle and Diseases of Civilization”

Cordially,

Loren Cordain, Ph.D., Professor Emeritus

Pedro Bastos MA MS Ph.D., candidate in Medical Sciences at Lund University, Sweden; International College of Human Nutrition and Functional Medicine

Maelan Fontes MS Ph.D., candidate in Medical Sciences at Lund University, Sweden

Oscar Picazo MSc, Ph.D., candidate in Human Nutrition; Nutriscience Education and Consulting Lda, Lisbon (Portugal)

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