Category Archives: Paleo Theory

Ever Heard of Paleolithic Diet Pioneer Arnold De Vries?

paleo diet, Paleolithic diet, hunter-gatherer diet

Not Arnold Paul De Vries or Don Wiss, but a Huaorani hunter in Ecuador

Don Wiss turned me on to another “modern” paleo diet pioneer, Arnold Paul De Vries, who wrote a 1952 book called Primitive Man and His Food. I even found the book on the Internet a few months ago, perhaps in violation of copyright. I can’t find it now. You can request a digital copy of the book here.

I read his thoughts on the diets of North American Indians before my other duties interrupted me.

Steve Parker, M.D.

Evolutionary Aspects of Obesity, Insulin Resistance, and Cardiovascular Risk

paleo diet, Paleolithic diet, hunter-gatherer diet

Huaorani hunter in Ecuador

Spreadbury and Samis have a review-type article in Current Cardiovascular Risk Reports. Here’s the abstract:

Cardiovascular disease (CVD) is still virtually absent in those rare populations with minimal Western dietary influence. To date, exercise, altered fats, fibre, anti-oxidants or Mediterranean diet do not appear to overcome the discrepancy in CVD between hunter-gatherer and Western populations. The CVD risk factors of obesity and diabetes are driven by increased caloric intake, with carbohydrates potentially implicated. Paradoxically, non-Westernized diets vary widely in macronutrients, glycemic and insulinemic indices, yet apparently produce no obesity or CVD regardless, even with abundant food. ‘Ancestral’ grain-free whole-food diet may represent the best lifestyle intervention for obesity and CVD. Such diets are composed of the cells of living organisms, while Western grains, flour and sugar are dense, acellular powders. Bacterial inflammation of the small intestine and vagal afferents appears a crucial step in leptin-resistance and obesity. Therefore it may be important that the Western diet resembles a bacterial growth medium.

You may remember Spreadbury’s name from his theory about acellular carbohydrates causing obesity via alterations in gut microorganisms. Spreadbury is with the Gastrointestinal Diseases Research Unit, Queen’s University, Kingston, Ontario, Canada.

You can read the articles for yourself. The following are a few of the authors points I found interesting or want to remember.

Does physical activity explain differences in CVD between Westernized and non-Westernized Peoples? They say “maybe.”

Throughout the article are references to aboriginals like the Hadza, Kitavans, Ache, Shuar, Australian aborigines, and Inuits. I always take comparisons of them to modern Europeans with a grain of salt, because of potential genetic differences between the populations. Moreover, diet and activity levels are only two of myriad cultural differences.

Australian Aborigine in Swamp Darwin

Australian Aborigine in Swamp Darwin

Can dietary changes reduce the incidence of CVD? They say it’s unclear.

Regarding modern paleo diet trials, “All the studies with ad libitum eating [eat all you want] have reported a spontaneous reduction in caloric intake in the order of 15-30%.” (Three references.) “The reduced food intake appeared driven by a satiety increase that was apparently not explicable by energy density, fiber or macronutrient content.” (One reference.)

“In those eating a Westernized diet, carbohydrates are increasingly recognized as being associated with poor metabolic health.” Evidence? Only one reference cited: Zienczuk’s 2012 article on high arctic Inuits.

“…non-Westernized populations with excellent metabolic and cardiovascular health almost invariably have negligible dietary contribution from grains, as well as refined sugar.” No citations.

“For ‘western-style’ diets and most obesogenic diets tested, gut microbiota appear to play a crucial role in obesity.” That’s a bold statement. References? Only one, a mouse study.

The rest of the article is about Spreadbury’s acellular carb/obesity theory. He suggests that small intestine bacteria play a more prominent role than colonic germs. Bacterial-driven inflammation….

The authors provide an example of a grain-free whole-food diet. It’s unrestricted in fruit, leafy or root vegetables, unprocessed meats, eggs, fish, nuts (except peanuts), mushrooms, herbs and spices. Occasional foods to be eaten in moderation are legumes, rice, yogurt, milk, cheeses, sweet corn, palm oil/lard/olive oil, and salt. Avoid almost all processed foods, breads, cereals, cakes/cookies/donuts etc., refined sugars, dried or processed fruits, vegetable/seed oils, and processed meats. They advise a vitamin D supplement. I’m not sure if they came up with this diet on their own, or it’s S. Lindeberg’s outline.

A final quote:

The macronutrient independence of the health from ancestral diet suggests whole foods are more important to health than their macronutrient or other chemical components, and that good health is associated with unprocessed cellular foods. Flour, sugar and processed foods appear to be important drivers of Western metabolic dysfunction, overweight and inflammation, and may prove to have a profound impact on, or even be the initiators of cardiovascular disease.

I’m sure Spreadbury and Samis would agree we need more basic science and clinical research into these issues, involving human test subjects. Maybe I’m prejudiced, but I’m more interested in Asians, Africans, and Europeans than Shuar people.

Steve Parker, M.D.

Reference: Spreadbury, Ian and Samis, Andrew J.S. Evolutionary aspects of obesity, insulin resistance, and cardiovascular risk. Current Cardiovascular Risk Reports, April 2013, vol. 7, issue 2, pp. 136-146.

Another Review Article In Favor Of Paleolithic Eating

It’s in the Annual Review of Plant Biology. The authors promote fruit and vegetable consumption. A snippet from the 2013 article:

Our Paleolithic ancestors were hunter-gatherers, consuming diets rich in lean wild meat or fish, with relatively high consumption of fruits and green leafy vegetables. Our modern diets, in contrast, are high in saturated fats and starches, added sugars with high energy load, and “unnatural fats” such as transfats. Paleolithic diets, in contrast to those of simians and present-day hunter-gatherers, are estimated to have been approximately 75% fruit [that's news to me; reference is from S. Lindeberg]. In modern US diets, foods unavailable to Paleolithic societies—including dairy products, cereal grains, refined cereal flour, refined sugars, refined vegetable oils, and alcohol—on average make up 70% of total energy consumption. Of this, 50% is in the form of vegetable oils and refined sugars .Americans currently consume less than 60% of the US Department of Agriculture recommendations for vegetables and less than 50% of the recommendations for fruits.

h/t Bill Lagakos

Reference: Annu. Rev. Plant Biol. 2013. 64:19–46. This article’s doi:10.1146/annurev-arplant-050312-120142

The Mellberg Study: Paleo Diet and Obese Postmenopausal Women

Sweden's Flag. Most of the researchers involved with this study are in Sweden

Sweden’s Flag

Swedish researchers compared a Paleolithic-type diet against a lower-fat, higher-carb diet so often recommend in Nordic countries and in the U.S. Test subjects were obese but otherwise healthy older women. The study lasted two years. Dieters could eat as much as they wanted.

They found that the paleo-style dieters lost more weight, lost more abdominal fat, and lowered their trigyceride levels. When measured six months into the study, the paleo dieters had lost 6.5 kg (14 lb) of body fat compared to 2.6 (6 lb) kg in the other group.

Measured at two years out, the paleo dieters had lost 4.6 kg (10 lb) of body fat compared to 2.9 kg (6 lb) in the other group, but this difference wasn’t statistically significant.

The greatest weight loss was clocked at 12 months: Paleo dieters were down 8.7 (19 lb) kg compared to 4.4 kg (10 lb)  in the other group.

But this study was about more than weight loss. The investigators were also interested in cardiometabolic risk factors and overall body composition.

The Set-Up

I don’t know what the researchers told the women to get them interested. Weight loss versus healthier diet versus ?  This could have influenced the type of women who signed up, and their degree of commitment.

A newspaper ad got the attention of 210 women in Sweden; 70 met the inclusion criteria, which included a body mass index 27 or higher and generally good health. Average age was 60. Average BMI was 33. Average weight was 87 kg (192 lb). Average waist circumference was 105 cm (41 inches). The women were randomized into one of two diet groups (N=35 in each): paleolithic-type diet (PD) or Nordic Nutrition Recommendations diet (NNR). There were no limits on total caloric consumption. (Were the women told to “work on weight loss”? I have no idea.)

We don’t know the ethnicity of these women.

Here’s their version of the paleo diet:

  • 30% of energy (calories) from protein
  • 40% of energy from fat
  • 30% of energy from carbohydrate
  • high intake of mono- and polyunsaturated fatty acids
  • based on lean meat, fish, eggs, vegetables, fruits, berries, and nuts
  • additional fat sources were avocado and oils (rapeseed [canola] and olive) used in dressings and food preparation
  • cereals (grains), dairy products, added salt and refined fats and sugar were excluded
  • no mention of legumes, potatoes, or tubers

The NNR diet:

  • 15% of energy from protein
  • 25-30% of energy from fat
  • 55-60% of energy from carbohydrate
  • emphasis on high-fiber products and low-fat dairy products

Over the 24 months of the study, each cohort had 12 group meetings with a dietitian for education and support, including “dietary effects on health, behavioral changes and group discussion.”

Various blood tests and body measurements were made at baseline and periodically. Body measurements were made every six months. Body composition was measured by dual energy x-ray absorptiometry. Diet intake was measured by self-reported periodic four-day food records.

Stockholm Palace

Stockholm Palace

Results

30% of participants (21) eventually dropped out by the end of the study and were lost to follow-up, leaving 27 in the PD group and 22 in the NNR cohort.

Food record analysis indicated the PD group indeed reduced their carb intake while increasing protein and fat over baseline. Baseline macronutrient energy percentages were about the same for both groups: 17% protein, 45% carb, 34% (I guess the percentages don’t add to 100 because of alcohol, which wads not mentioned at all in the article.) Two years out, the PD group’s energy sources were 22% protein, 34% carb, 40% fat. For the NNR group, the energy sources at two years were 17% protein, 43% carb, and 34% fat. As usual, dietary compliance was better at six months compared to 24 months. The PD group failed to reach target amounts of protein energy (30%) at six and 24 months; the NNR group didn’t reach their goal of carbohydrate energy (55-60%). The PD group ate more mono- and poly unsaturated fatty acids than the NNRs.

In contrast to the food record estimates of protein intake, the urine tests for protein indicated poor adherence to the recommended protein consumption in the PD group (30% of energy). Both groups ate the same amount of protein by this metric. (This is an issue mostly ignored by authors, who don’t say which method is usually more accurate.)

“Both groups had statistically significant weight loss during the whole study, with significantly greater weight loos in the PD group at all follow up time points except at 24 months.” Largest weight loss was measured at 12 month: 8.7 kg (19 lb) in the PD group versus 4.4 kg (10 lb) in the NNRs.

The PD group lost 6.5 kg (14 lb) of body fat by six months but the loss was only 4.6 kg (10 lb) measured at 24 months. Corresponding numbers for the NNR group were 2.6 and 2.9 kg (about 6 lb). So both groups decreased their total fat mass to a significant degree. The difference between the groups was significant (P<0.001) only at six months. The greatest weight loss was clocked at 12 months: PD dieters were down 8.7 kg (19 lb) compared to 4.4 kg (10 lb) in the NNRs. Both groups saw a significant decrease in waist circumference during the whole study, with a more pronounce decrease in the PD group at six months: 11 versus 6 cm (4.3 versus 2.4 inches).

Fasting blood sugars, fasting insulin levels, and tissue plasminogen activator activity didn’t change.

Both groups had improvements in blood pressure, heart rate, c-reactive protein, LDL cholesterol, PAI-1 activity, and total cholesterol. The PD group saw a greater drop in triglycerides (by 19% at two years, but levels were normal to start with at 108 mg/dl or 1.22 mmol/l).

Reported daily energy intake fell over time for both groups, without statistically significant differences between them.

paleo diet, Steve Parker MD, diabetic diet

Sweet potato chunks brushed with olive oil, salt, pepper, and rosemary. Ready for the oven.

Discussion

As measured at six months, the paleo dieters lost 10% of their initial body weight, compared to 5% in the NNR group. That’s worth something to many folks. However, the researchers didn’t find much, if any, difference in the groups in terms of cardiometabolic risk factors. They wonder if that reflects the baseline healthiness of these women. Would a sicker study population show more improvement on one of the diets?

I’m surprised the NNR group lost any weight at all. In my experience it’s hard for most folks to lose weight and keep it off while eating as much as they want, unless they’re eating very-low-carb. We’ve seen short-term weight loss with ad libitum paleo diets before (here for example, and here, and here). I bet the women signing up for this study were highly motivated to change. 

Legumes and potatoes are a debatable part of the paleo diet. Most versions exclude legumes. We don’t know if these women ate legumes and potatoes. Other than this oversight, the study paleo diet is reasonable.

The authors noted that the paleo diet group failed to reach their protein intake goal (30% of total calories), and suggested reasons “such as protein-rich foods being more expensive, social influences on women’s food choices or a lower food preference for protein-rich food among women.”

The results of this study may or may not apply to other population subgroups and non-Swedes.

The authors write:

In conclusion, a Palaeolithic-type diet during two years with ad libitum intake of macronutrients, including an increased intake of polyunsaturated fatty acids and monounsaturated fatty acids reduces fat mass and abdominal obesity with significantly better long-term effect on triglyceride levels vs an NNR diet. Adherence to the prescribed protein intake was poor in the PD group suggesting that other component of the PD diet are of greater importance.

Does this study have anything to do with diabetes? Not directly. But it suggests that if an overweight diabetic needs to lose excess body fat without strict calorie control, a lower-carb paleo-style diet may be more effective than a low-fat, higher-carb diet. I would have liked to have seen lower fasting blood sugar and insulin levels in the paleo dieters, but wishing doesn’t make it so.

Steve Parker, M.D.

PS: Carbsane Evelyn has taken a look at this study and blogged about it here and here. I’ve not read those yet, but will now.

Reference: Mellberg, C., et al (including M. Ryberg and T Olsson). Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. European Journal of Clinical Nutrition, advance online publication January 29, 2014. doi: 10.1038/ejcn.2013.290

Do Intestinal Parasites Help Prevent Atherosclerosis?

A trio of Indian researchers suggest a new hypothesis to explain the modern pandemic of atherosclerosis (hardening of the arteries). They repeat the notion that atherosclerosis is uncommon in modern hunter-gatherers. But why?

Reviewing evolution-linked risk factors suggests that there are four aspects to the etiology of atherosclerosis namely, decreased intestinal parasitism, oversensitivity of evolutionarily redundant mast cells, chronic underactivation of AMPK (cellular energy sensor) and a deficiency of vitamin D. A combination of these four causes appear to have precipitated the atherosclerosis pandemic in modern times.

Click for the abstract. Pretty far out stuff. I haven’t read the full article. The authors are in the Departments of Pharmacology and Pharmacy Practice.

Have You Heard It’s Better to Squat Than Sit While Defecating?

It may prevent hemorrhoids, according to a writer at Slate.

I first heard about this debate around three years ago, probably at Mark’s Daily Apple. You don’t hear about it much now. An article at Huffington Post dredged it up recently. The Post will also tell you 14 other things you’re doing wrong in the bathroom. Take’em with a grain of salt.

I only bring this to your attention in case you’re new to the paleo lifestyle. It’s not just about food, ya know. Modern toilets haven’t been around forever. Billions of us still squat to poop, just like our ancestors.

 

 

Dr. Guyenet Makes a Case for Beans in the Paleo Diet

As an introduction, he writes…

The canonical Paleolithic diet approach excludes legumes because they were supposedly not part of our ancestral dietary pattern.  I’m going to argue here that there is good evidence of widespread legume consumption by hunter-gatherers and archaic humans, and that beans and lentils are therefore an “ancestral” food that falls within the Paleo diet rubric.  Many species of edible legumes are common around the globe, including in Africa, and the high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking.

Richard Wrangham thinks hominins started cooking with fire as long as 1.8 million years ago. There’s no expert consensus yet.

Read the rest.

The Argument Against Starches, Safe or Otherwise

Lifextension argues it as well as anyone I’ve read. Some quotes:

Chimpanzees produce salivary amylase to digest fruit; similarly, carnivores also possess amylase in order to process the glycogen residing in muscle meat. Moreover, animals fed alternatives to their natural diet will produce amylase in amounts corresponding to the quantity of carbohydrates consumed. Humans too have their own primordial amylase gene copy; we have possessed it ever since we were primates. The second copy mutation occurred somewhere between 100 – 200,000 years ago, however this may have resulted even more recently, as single nucleotide polymorphisms and copy number mutations can result in just thousands of years. The additional – and currently incomplete – copies occurred at the very most, around 25,000 years ago, but most plausibly they came about around 10,000 years ago, concurrent with the onset of agriculture, and confirming that high starch consumption was a historically late phenomenon. Many present day human populations from low-starch consuming ancestries still only have two copies, indicating that adaptation to high-starch consumption was not globally widespread.

***

Moreover, the current evidence engendered from nitrogen stable isotope analysis of hominin bone data – being studied by Professor Michael Richards and the Max Planck Institute for Evolutionary Anthropology – has confirmed that our human ancestors truly were high-level carnivores. In fact, one-hundred percent of the early hominin bones studied from Upper Palaeolithic Europe reveal an even more carnivorous stable isotope footprint than that of foxes and wolves; while, comparatively, the data from omnivores such as pigs or the Brown Bear validates that these species truly did have an omnivorous diet.

Read the whole enchilada. The debate continues.

I’ve Never Had Much Interest in the Kitavans…

…but maybe you have.

If so, click over to Science-Based Medicine for Dr. Harriet Hall’s thoughts on them and Staffan Lindeberg’s seminal nutrition study. This is her second recent post on ancestral diets (aka paleo). A snippet:

I am always suspicious of initial reports of unusually healthy or long-lived groups in remote areas, because I have so often seen such reports disconfirmed by subsequent investigations. Lindeberg’s studies were done in the early 90’s and have not been confirmed by other studies in the ensuing two decades. In the Kitava study, the ages of subjects were not objectively verifiable, but were estimated from whether or not they remembered significant historical events. The absence of heart disease and stroke was deduced by asking islanders if they had never known anyone who had the symptoms of either condition. This was reinforced by anecdotal reports from doctors who said that they didn’t see those diseases in islanders. EKGs were done on the Kitavans, but a normal EKG does not rule out atherosclerosis or cardiovascular disease. I’m not convinced that we have enough solid data to rule out the presence of cardiovascular disease or other so-called “diseases of civilization” in that population.

You can guess where this is going.

Dr. Stephan Guyenet chimes in with cogent comments.

Read the whole thing.

A Theoretical Framework For Evolutionary Medicine

paleo diet, Paleolithic diet, hunter-gatherer diet

Huaorani hunter in Ecuador

If you’re scientifically inclined, you’ll enjoy perusing the following article. Otherwise, quit now before it’s too late.

Lifestyle and nutritional imbalances associated with Western diseases: causes and consequences of chronic systemic low-grade inflammation in an evolutionary context,” by Begoña Ruiz-Núñez, Leo Pruimboom, D.A. Janneke Dijck-Brouwer, and Frits A.J. Muskiet. It’s in the Journal of Nutritional Biochemistry, vol. 24, issue 7, pp. 1183-1201. http://dx.doi.org/10.1016/j.jnutbio.2013.02.009,

Here’s the abstract:

In this review, we focus on lifestyle changes, especially dietary habits, that are at the basis of chronic systemic low grade inflammation, insulin resistance and Western diseases. Our sensitivity to develop insulin resistance traces back to our rapid brain growth in the past 2.5 million years. An inflammatory reaction jeopardizes the high glucose needs of our brain, causing various adaptations, including insulin resistance, functional reallocation of energy-rich nutrients and changing serum lipoprotein composition. The latter aims at redistribution of lipids, modulation of the immune reaction, and active inhibition of reverse cholesterol transport for damage repair. With the advent of the agricultural and industrial revolutions, we have introduced numerous false inflammatory triggers in our lifestyle, driving us to a state of chronic systemic low grade inflammation that eventually leads to typically Western diseases via an evolutionary conserved interaction between our immune system and metabolism. The underlying triggers are an abnormal dietary composition and microbial flora, insufficient physical activity and sleep, chronic stress and environmental pollution. The disturbance of our inflammatory/anti-inflammatory balance is illustrated by dietary fatty acids and antioxidants. The current decrease in years without chronic disease is rather due to “nurture” than “nature,” since less than 5% of the typically Western diseases are primary attributable to genetic factors. Resolution of the conflict between environment and our ancient genome might be the only effective manner for “healthy aging,” and to achieve this we might have to return to the lifestyle of the Paleolithic era as translated to the 21st century culture.

I encourage you to read the whole article if you’re interested in such things. I’ll only mention certain concepts in this post if I want to learn or remember them for my own purposes.

The authors stress our large brains’ constant need for energy from glucose. This is how they explain our propensity to develop insulin resistance:

A glucose deficit leads to competition between organs for the available glucose. As previously mentioned, this occurs during fasting [and starvation], but also during pregnancy and infection/inflammation. Fasting is characterized by a generalized shortage of glucose (and other macronutrients), but in case of pregnancy and inflammation we deal with active compartments competing with the brain for the available glucose, i.e., the growing child and the activated immune system, respectively. During competition between organs for glucose, we fulfill the high glucose needs of the brain by a reallocation of the energy-rich nutrients, and to that end, we need to become insulin resistant.

During starvation and times of infection or inflammation, we divert glucose to our brains or immune systems via insulin resistance in certain tissues. These tissues can then use less glucose and more fat for energy. “…the adipose tissue compartment will be encouraged to distribute free fatty acids, while the liver will be encouraged to produce glucose via gluconeogenesis and to distribute triglycerides via very low-density lipoprotein (VLDL).”

This reallocation of energy—the aim of the process above—and the compensatory hyperinsulinemia “are meant for short-term survival, and their persistence as a chronic state are at the basis of the ultimate changes that we recognize as the symptoms of the metabolic syndrome, including the changes in glucose and lipid homeostasis and and the increasing blood pressure. For example, the concomitant hypertension has been explained by a disbalance between the effects of insulin on renal sodium reabsorption and NO-mediated vasodilatation, in which the latter effect, but not the first, becomes compromised by insulin resistance, causing salt sensitivity and hypertension.”

I warned you to get out before it was too late!

Looks like a great place to hike

Looks like a great place to hike

I don’t ever recall reading how much energy our immune system uses. The authors write:

During infection/inflammation we deal with the metabolic needs of an activated immune system for acute survival. The inactive immune system consumes about 23% of our basal metabolism, of which as much as 69% derives from glucose (47%) and the glycogenic amino acid glutamine (22%). Upon activation, the energy requirement of our immune system may increase with about 9–30% of our basal metabolic rate. In multiple fractures, sepsis and extensive burns, we deal with increases up to 15–30, 50, and 100% of our basal metabolism, respectively.

The activated immune system, they say, functions mainly on glucose.

Summarizing thus far, we humans are extremely sensitive to glucose deficits, because our large brain functions mainly on glucose. During starvation, pregnancy and infection/inflammation, we become insulin resistant, along with many other adaptations. The goal is the reallocation of energy-rich substrates to spare glucose for the brain, the rapidly growing infant during the third trimester of pregnancy, and our activated immune system that also functions mainly on glucose. Under these conditions, the insulin resistant tissues are supplied with fatty acids. Other goals of the changes in the serum lipoprotein composition are their role in the modulation of the immune response by the clearance of LPS [lipopolysaccharides] during infection/inflammation and the redirection of cholesterol to tissues for local damage repair. The metabolic adaptations caused by inflammation illustrate the intimate relationship between our immune system and metabolism. This relation is designed for the short term. In a chronic state it eventually causes the metabolic syndrome and its sequelae. We are ourselves the cause of the chronicity. Our current Western lifestyle contains many false inflammatory triggers and is also characterized by a lack of inflammation suppressing factors.

The authors list many familiar components of the Western lifestyle that can cause chronic systemic low-grade inflammation, “which in turn leads to chronically compromised insulin sensitivity, compensatory hyperinsulinemia and, eventually, the diseases related to the metabolic syndrome”:

  • the consumption of saturated fatty acids and industrially produced trans fatty acids
  • a high ω6/ω3 fatty acid ratio
  • a low intake of long-chain polyunsaturated fatty acids (LCP) of the ω3 series (LCPω3) from fish (EPA and DHA are most important)
  • a low status of vitamin D and vitamin K and magnesium
  • the “endotoxemia” of a high-fat low-fiber diet
  • the consumption of carbohydrates with a high glycemic index and a diet with a high glycemic load
  • a disbalance between the many micronutrients that make up our antioxidant/pro-oxidant network
  • a low intake of fruit and vegetables
  • an abnormal composition of the bacterial flora in the mouth, gut, and gingivae
  • chronic stress
  • smoking, second-hand smoke, and environmental pollution
  • insufficient physical activity
  • insufficient sleep
  • excessive alcohol consumption
  • low fiber intake
  • meat from domesticated animals
  • obesity

“Homo sapiens emerged about 160,000 years ago in East-Africa.”

In contrast to some (e.g., John Hawks?) who believe we are rapidly evolving, these authors think that our genome, “with an average effective mutation rate of 0.5% per million years,” still overwhelmingly reflects the Paleolithic era.

They support their contentions with 334 references.

Steve Parker, M.D.