Category Archives: Paleo Theory

Free Online Paleoanthropology “Textbook”: John Hawks Blog

Posted on October 25, 2011 | 4 comments

I’ve never seriously studied anthropology, paleontology, or paleoanthropology.  When I read someone who seems or claims to be an expert on paleoanthropology or certain aspects of evolution, it requires a degree of trust on my part. 

(I have a stronger background in evolution, thanks to a B.S. degree in Zoology.  I was thoroughly indoctrinated in the mid-1970s.)

It was a slow day at work, so I just spent a couple hours perusing the blog of an actual paleoanthropologist named John Hawks.  It’s a massive database that may be the equivalent of a paleoanthropology textbook.  Naturally, it will reflect the biases of the author, if any (and we all have some, don’t we?) . 

Some interesting things you’ll find there:

Regarding the pace of human evolution in the Neolithic period, Artemis P. Simopoulos (with The Center for Genetics, Nutrition and Health in 2009) has a different view:

The spontaneous mutation rate for nuclear DNA is estimated at 0.5% per million years.  Therefore, over the past 10,000 years there has been time for very little change in our genes, perhaps 0.005%.  In fact, our genes today are very similar to the genes of our ancestors during the Paleolithic period 40,000 years ago, at which time our genetic profile was established.

I dunno; you decide.

Steve Parker, M.D.

Reference:  Simopoulos, Artemis P.  Evolutionary aspects of the dietary omega-6:omega-3 fatty acid ratio: medical implications.  World Review of Nutrition and Dietetics, 100 (2009): 1-21. Epub August 17, 2009.

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Posted in Genetics, Paleo Theory

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Old Stone Age Diet Depended On Latitude

Posted on October 4, 2011 | 3 comments

There isn’t any single Stone Age diet, according to J.A.J. Gowlett, who (whom?) I assume is an archeologist with the University of Liverpool.

(I was tempted to write “there isn’t a monolithic Stone Age diet.”  Get it?  “Lith” is Greek or Latin for “stone.”)

This is probably old new for you guys who have been interested in the paleo diet for much longer than I.

Here are a few more of Gowlett’s ideas:

  • The Stone Age is is more accurately referred to as the Old Stone Age.
  • Hominids (the family of human ancestors) branched off from ape ancestors around eight to 10 million years ago.
  • Roots and tubers have been a part of our ancestral diet for perhaps as long as three million years,  which “places starchy carbohydrate consumption as part of the deep ancestry of human beings.”
  • Meat eating assumed greater importance about two million years ago.
  • Migration to colder environments necessitated more meat consumption because plant foods were more limited.
  • Our ancestors migrated from tropical to temperate latitudes about by 1.7 million years ago.
  • Early humans began using fire for cooking between 500,000 to 1.5 million years ago.
  • Neanderthals were heavily carnivorous.
  • “Ancestors of modern humans are now believed to have evolved in the tropics, probably in Africa, from about 200,000 years ago.”  Their diet was perhaps 70% plant-based.
  • “In contrast, modern humans entering Europe 40,000 years ago would have adopted a meat-based diet by necessity, and maintained this over hundreds of generations.”
  • “Modern hunters and gatherers echo the variety of past diets, ranging from largely plant based in the tropics, to being also heavily meat based in the arctic.”
  • No ancient human population depended heavily on cereals or non-human milk.  “Fruit certainly came first of all….”

Potential Implications For a Paleo Diabetic Diet (highly speculative)

Diabetics with tropical lineage may do better with a plant-based diet.  Those with northern European ancestry may do better with meat-based.

Paleo diets likely had very high fiber contents, reflecting the degree to which they were plant-based.  We’re looking at 70+ grams of fiber daily.  That much fiber would tend to reduce the effect of carbohydrate on blood sugar levels.

Fruits and roots have a high concentration of carbohydrate, with potential adverse effects on blood sugar (raising it, of course).  Diabetics eating paleo-style may need to avoid or limit certain fruits and roots: the ones with lower fiber content and higher glycemic index.  Blood sugar responses will vary from one diabetic to another.  Monitor blood sugar levels one or two hours after carb consumption to learn your idiosyncratic response.

Steve Parker, M.D.

Reference: Gowlett, J.A.J.  What actually was the Stone Age diet?  Journal of Nutritional and Environmental Medicine, 13 (2003): 143-147.

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Posted in Diabetic Diet, Low-Carb, Paleo Diet, Paleo Theory

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How Active Were Stone Age Humans?

Posted on October 3, 2011 | 2 comments

The Paleolithic standard for daily physical activity was about 490 calories (2.1 MJ), according to estimates by S. Boyd Eaton and Stanley B. Eaton in a 2003 article.

The Eatons estimated late Stone Age activity levels based on recent hunter-gatherer societies and skeletal remains from 50,000 to 20,000 years ago.  In case you didn’t know, our bones reflect how much work we ask them to do.  Heavy physical work loads over time lead to thicker, stronger bones, even changing the cross-sectional shape of long bones from round to oval. 

From a diabetes viewpoint, the scientists expect that our prehistoric ancestors had excellent insulin sensitivity in view of their relatively larger muscle mass and high activity levels.  They would have been less prone to develop type 2 diabetes.

Habitual high levels of physical activity of our ancestors put them in the same class as today’s elite cross-training athletes.

The Eatons suggest that replication of the Paleolithic activity level would require we exercise about an hour a day, not the 30 minutes recommended by some public health authorities. 

Steve Parker, M.D.

Reference: Eaton, S. Boyd, and Eaton, Stanley B.  An evolutionary perspective on human physical activity: implications for health.  Comparative Biochemistry and Physiology: Part A Molecular and Integrative Physiology, 136 (2003): 153-159.

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Posted in Exercise, Paleo Theory

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Dan Pardi Summarizes Five Popular Paleo Diet Versions

Posted on September 29, 2011 | 3 comments

Dan Pardi has a recent blog post outlining five popular versions of the paleo diet (aka Stone Age diet, caveman diet, paleolithic diet).  (I don’t like the term “caveman diet.”)  Although it’s a short post, I haven’t read it yet.

Medical and nutrition science researchers need a concensus definition, if possible, before they begin their investigations.  I suspect they’ll end up with several definitions, as we’ve seen with the Mediterranean diet.

Steve Parker, M.D.

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Posted in Paleo Movement, Paleo Theory

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Paleolithic Nutrition: Twenty-Five Years Later

Posted on September 29, 2011 | 16 comments

Melvin Konner and S. Boyd Eaton wrote a review article for Nutrition in Clinical Practice that update’s their seminal New England Journal of Medicine  paleo nutrition article of 1985.  They took a fresh look at recent  data on modern hunter-gatherer societies as well as advances in anthropology. 

NEJM likely has much wider circulation, so it’s too bad the update wasn’t published there.

I’ve written previously about the history of the modern paleo movement.  I consider S. Boyd Eaton and Melvin Konner two of the founders. 

I wanted to share a few tidbits from the new article:

  • The transition from hunting/gathering to farming (about 10,000 year ago) saw a decrease in body size and robustness, plus evidence of nutritional stress
  • Modern humans migrated away from Africa between 50,000 and 100,000 years ago
  • Levels of muscular and aerobic fitness in ancestral groups are much higher than modern societies, with a concomittant higher level of calorie consumption
  • Average life expectancies in pre-industrial hunter-gatherer (H-G) groups was only 30-35 years, but much of this low number simply reflects high infant and child death rates
  • H-G deaths overwhelmingly reflect infectious diseases
  • H-G groups had a high degree of dependence on plant foods
  • Cooking has been important to humans for at least 230,000 years, if not longer
  • Fish and shellfish are more important food sources than these authors thought 25 years ago
  • Ancestral H-G groups derived 35 to 65% of diet (calories, I guess) from animal flesh
  • Game animals have more mono- and polyunsaturated fatty acids than supermarket meat
  • H-G diets are higher in fat than they once thought: the new range is 20 to 35% of calories
  • H-G diet omega-6: omega-3 ratio was 2:1, in contrast to the modern Western ratio of 10:1
  • H-G groups eat more protein than they once thought
  • Carbohydrate consumption of H-G groups varied from about 35 to 65% of calories.  (I’ve written elsewhere about the carb content of paleo diets.)
  • Nearly all H-G carbs are from vegetables and fruits, which have more favorable glycemic responses than grains and concentrated sugars
  • Uncultivated fruits and veggies have much more fiber than commercial ones (13 versus 4 g fiber per 100 g of food)
  • H-G diets have at least 70 g of fiber daily
  • Sodium in H-G diets is very low: 800 mg/day

The Diet-Heart Hypothesis is the idea that dietary total and saturated fat, and cholesterol, cause or contribute to atherosclerosis (hardening of the arteries), leading to heart attacks and strokes.  Konner and Eaton still believe the theory is valid for fats, but not cholesterol.  The latest evidence is that even total and saturated fat are minimally or unrelated to atherosclerosis. 

They also believe total fat, due to its caloric load, is an important contributor to obesity and type 2 diabetes.  (I agree that my be true if you eat a lot of carbs with fat.)

Konner and Eaton review the very few clinical studies—a grand total of four—that apply a paleo diet to modern humans.  Results support their theory that paleo-style eating has healthful metabolic effects.

Their conception of a paleo food pyramid is a base of high-fiber vegetables and fruits, the next tier up being meat/fish/low-fat dairy (!?) (all lean), then a possible tier for whole grain (admittedly very unusual), with a small peak of oils, fats, and refined carbohydrates.

They recommend high activity levels, including resistance exercise, flexibility, and aerobics, burning over 1,000 cals/day exclusive of resting metabolism.

They also seem to favor small amounts of alcohol—not generally considered paleo—to reduce heart disease risk, admitting that “…the HG model cannot answer all questions.”

Eaton and Konner suggest the following as the “estimated ancestral diet“:

  • Carbohydrates, % daily energy                 35-40
  • Protein, % daily energy                                 25-30
  • Fat, % daily energy                                          20-35
  • Added sugar, % daily energy                            2
  • Fiber, g/day                                                        >70
  • EPA and DHA*, g/day                                    0.7-6
  • Cholesterol, mg/day                                       500+
  • Vitamin C, mg/day                                           500
  • Vitamin D, IU/day                                4,000 (sunlight)
  • Calcium, mg/day                                       1,000-1,500
  • Sodium, mg/day                                         under 1,000
  • Potassium, mg/day                                         7,000

*Eicosapentaenoic acid and docosahexaenoic acid

Konner and Eaton call for more randomized controlled studies of the paleo diet.  These studies will need to define the paleo diet carefully.  Their definition is probably as good as any, if not the best.  Of course, the listed nutrients should come from minimally processed, natural foods.  We just need Loren Cordain‘s and Staffan Lindeberg‘s  input on a concensus definition of the paleo diet, then we’re ready to rock’n’roll.

Steve Parker, M.D.

Reference:

Konner, Melvin and Eaton, S. Boyd.  Paleolithic Nutrition: Twenty-Five Years Later.  Nutrition in Clinical Practice, 25 (2010): 594-602.  doi: 10.1177/0884533610385702

Eaton, S.B. and Konner, M.  Paleolithic nutrition: a consideration of its nature and current implications.  New England Journal of Medicine, 312 (1985): 283-289.

 

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Posted in Low-Carb, Paleo Diet, Paleo Movement, Paleo Theory

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