From Michael Eades' latest blog post:
http://www.proteinpower.com/drmike/low-carb-diets/are-we-meat-eaters-or-vegetarians-part-iii/#more-4681
A little over two years ago I wrote a couple of posts arguing that we
cut our ancestral teeth on meat, and that contrary to all the
vegetarian blather about colon length, tooth structure, etc., the
archeological and anthropological convincingly demonstrates we were
descended from meat eaters, not vegetarians. (Click here and here for
those posts.) A couple of recent developments have now inspired me to
write a third.
First, I noticed in both talking with people at the Ancestral Health
Symposium last August and attending a number of the talks that many
followers of their own version of the ancestral diet are dismayingly
including more and more carbohydrates. And recommending more to their
followers.
When MD and I wrote Protein Power in the mid 1990s, we used the
Paleolithic diet as an argument for the efficacy of the low-carb diet.
If pre-agricultural man evolved in a milieu devoid of
carbohydrate-dense foods, we posited, then natural selection should
have culled those who didn?t thrive on such fare, leaving us, the
descendants, powered by metabolic processes that performed better on
protein and fat substrates. If the rampant obesity and diabetes (we
just thought it was rampant then) was a consequence of a diet we
weren?t designed for, then switching to one that better suited us
metabolically should produce substantial changes to the good. Which
it undeniably does.
I can?t help but recall the great quote by Dr. Blake Donaldson, who
changed the complexion of his practice in New York after spending some
time with Vilhjalmur Stefansson. Wrote Dr. Donaldson in Strong
Medicine, his book about an almost all meat diet:
During the millions of years that our ancestors lived by hunting,
every weakling who could not maintain perfect health on fresh meat and
water was bred out.
Now, it seems, many who have taken to the Paleo diet have started to
drift from the Paleo-is-basically-low-carb paradigm into the
Paleo-is-anything-that-isn?t-Neolithic paradigm. And although
Neolithic man grew all sorts of crops, most Paleo dieters consider
only grains to be truly Neolithic foods. Some Paleo dieters take it a
step further and argue that since pre-agricultural man couldn?t have
domesticated animals (other than perhaps canids of some sort), then he
couldn?t have eaten dairy products. So, those Paleo purists avoid
grain and dairy products. Both the dairy and non-dairy Paleo dieters,
however, are starting to include larger amounts of carbohydrates ?
primarily starch ? into their diets on the presumption that Paleo man
would have eaten it.
I have no doubt that Paleo man would have been face down in a box of
donuts had he been given the opportunity. But he wasn?t. Nor was he
often presented with the opportunity to indulge in a carb fest
composed of high-starch fruits and vegetables. Maybe in the fall when
the fruit ripened (if he could beat the birds and bugs to it), but not
much of a chance during the rest of the year.
(I am aware that Denise Minger put up a post not too long ago showing
all the high-starch, high-sugar tropical fruits available in tropical
areas, intimating that early man must have consumed these and,
therefore, should have evolved to do okay on high-carb diets. Problem
with this reasoning is that archaic homo sapiens migrated out of
tropical areas anywhere from 60,000 to 150,000 years ago and went
through the crucible of natural selection in other less fruit-laden
climes. People of European descent certainly had ancestors who could
not avail themselves of tropical fruits at any time.)
The second event driving me to write is a line out of a guest post on
Richard Nikoley?s Free the Animal blog by Darrin Carlson titled ?The
Five Failings of Paleo.? In Mr. Carlson?s own words, here is Paleo
Fail #1:
We Don?t REALLY Know What Our Ancestors Ate. [Bold and caps in the original.]
I disagree for a couple of reasons. First, we can be pretty certain
what our European ancestors didn?t eat. They didn?t eat dwarf wheat,
Red Delicious apples, bananas, Bartlett pears or any other hybridized
or tropical fruits commonly available today. As far as we know, there
were no Paleo Luther Burbanks grafting and hybridizing plants to make
them bigger and sweeter. Our predecessors would have eaten whatever
plant foods were at hand, which is pretty much what you still find if
you go out in the woods today. They would have had to battle the birds
and other wildlife to get to these fruits, and would have had them
available only seasonally.
The second reason I disagree is alluded to in a way by Mr. Carlson in
his explanation of Fail #1: Said he:
We have yet to find a magic phone booth that will transfer us back
through time?Bill and Ted notwithstanding?to directly observe how our
great-times-450-grandparents lived.
Actually we do have such a ?magic phone booth? available to us, or at
least to those of us who know how to use it. It?s an isotope ratio
mass spectrometer, and its use has been refined over the past 30-40
years to allow us to peer back in time and calculate what our
ancestors ate.
I learned about this ?magic phone booth? in the fall of 2000 in
Hamburg, Germany where MD and I attended a great conference titled
Meat and Nutrition. After the last talk, on a cold, dreary, foggy,
drizzly afternoon, MD, Loren Cordain and I lit out to make a
pilgrimage to Indra and the Kaiserkeller, the dives where the Beatles
had gotten their start in the early 1960s. We asked Michael Richards,
a professor at the University of Bradford to join us. On the first
morning of the meeting, Michael had given a riveting talk on the use
of stable isotopes to determine the diet of early man, and I wanted to
find out more.
After roaming the Beatles early haunts, we decamped to a Hamburg
coffee house to get warm. I asked many questions about the stable
isotope methodology and have followed the growing literature on it
since. Michael has turned into an academic superstar and is now at
the prestigious Max Planck Institute for Evolutionary Anthropology in
Leipzig, Germany, where he continues to publish his work on the
isotopic analysis of the diet of early man.
Let?s take a look at the ?magic phone booth? of stable isotope
analysis and see what it shows. The whole notion is fairly complex so
I?m torn between making its science simple enough for Homer Simpson to
understand, which really doesn?t do the technique justice, or making
it unnecessarily difficult. I?m shooting for something in between.
As most everyone knows, atoms are composed of protons, electrons and
neutrons. The number of protons gives an element its atomic number.
A given element always has the same number of protons but can have
varying numbers of neutrons. Carbon, for example, has six protons
(and an atomic number of 6). But the carbon atom can have 6, 7 or 8
neutrons. All three versions are still carbon, but the atoms vary by
the number of neutrons. These different versions are called isotopes,
so basically isotopes are atoms of the same element with the same
number of protons but differing numbers of neutrons. The atomic mass
of an atom is determined by the number of protons and neutrons it
contains, so although carbon always carries the atomic number of 6,
carbon has three different atomic masses: 12C, 13C and 14C.
Carbons with an atomic mass of 12 and 13 (12C, 13C) are stable whereas
14C (pronounced carbon 14) disintegrates radioactively over time.
This radioactive decay is what allows scientists to determine the age
of organic materials up to about 40,000 years old. The discovery of
natural radioactivity of 14C and its usefulness in determining age
garnered Willard Libby the 1960 Nobel Prize in Chemistry. Although
the unstable isotopes such as 14C have their uses, we are concerned
here with the stable isotopes. Primarily 12C and 13C and 14N and 15N
(nitrogen 14 and 15). From these four stable isotopes, we can learn a
lot about the diet of early man.
Nuclear weapons started adding 14C into the atmosphere in the mid
1900s, so the average ratio of 12C, 13C and 14C have change slightly.
Since 12C and 13C are stable, there has been virtually no change in
the ratio between them over time. But the ratio of the two has been
found to differ from one carbon-containing material to another. For
instance, carbon dioxide generated from marine limestone contains more
13C than does carbon dioxide generated from burning wood. In general,
marine sources have greater amounts of 13C than do terrestrial sources.
Just to make it a little more complex, when researchers run samples
through a mass spectrometer to determine the 13C/12C ratio, this ratio
is compared to an agreed standard. Then the difference between the
sample and the standard is called the relative 13C content, which is
designated by ?13C and measured in parts per thousand. (?) So if the
sample has a ratio less than the standard by 5 parts per thousand, it
is defined as having a ?13C value of ?5?.
Don?t worry about all the above ? just remember when you see ?13C from
now on, it refers to the ratio of 13C to 12C. Don?t despair. It will
be easier as we go along.
Of the dry weight of bone, a little over 25 percent is collagen, and
it is collagen that is the tissue of choice for stable isotope
analysis. Virtually all of the carbon and nitrogen in collagen comes
from protein, and since most protein in the human body ultimately
comes from protein in the diet, the carbon and nitrogen isotopes in
the collagen reflect the protein sources in the diet. And since the
stable isotope composition of collagen turns over very slowly, the
ratios of carbon and nitrogen stable isotopes reflect diet over about
an eight to ten year period.
Stable isotopes of both carbon and nitrogen occur in varying
proportions in different foods, and these proportions are passed along
to the animals, including humans, that ate these foods. By knowing
the proportions of the stable isotopes in various foods, we can
determine these foods by analyzing the stable isotopes in human
collagen.
Researchers are able to extract valuable data from the collagen of
ancient bones. Unfortunately ancient bones are not thick on the
ground, and since a part of the bone has to be destroyed to perform
the stable isotope analysis, these analyses are not done by the
thousands. Each time a skeleton or group of skeletons is unearthed,
Michael Richards and other stable isotope researchers try to snare a
little piece of bone and go at it with the mass spectrometer. This
kind of work has been done for several decades now, and the results ?
though painstakingly obtained one specimen at a time ? are
accumulating, and there is now a fairly substantial body of data. And
this data is remarkably uniform in what it shows of the dietary habits
of our ancient European ancestors.
The ?13C and ?15N figures reveal different information about the diet
of Paleo man. Since the 13C isotope is found in greater quantities in
the marine environment than in the terrestrial, a larger ?13C
indicates a diet higher in seafood protein whereas a lower ?13C is
associated with a diet composed primarily of protein foods from the
land. Researchers have accumulated considerable data on the ?13C of
seals and other such animals that spend their lives in the oceans
consuming other marine life to compare with the data gleaned from
bones of animals living on the land far from the sea. By noting how
the ?13C from ancient human bone compares to these extremes determines
whether the human dined on protein from terrestrial or marine sources
of from a combination of the two.
The ?15N tells a different story. ?15N basically tells us where an
animal or human is on the food chain. Basic plant foods maintain a
fairly constant ?15N value. When animals, typically herbivores, eat
these plant foods, the stable N isotope in the plant food tends to
concentrate by anywhere from 5-8 percent in the collagen of the
animal. So if the collagen of an animal is found to have, say, a 7
percent greater ?15N than the local flora, one can say the animal was
an herbivore. Animals that are known herbivores, when analyzed, fit
this spectrum.
Any animal, including man, that dines on herbivores will have collagen
sporting a ?15N that is about 7 percent greater than that found in the
herbivores that are the meal, a fact confirmed by stable isotope
analysis of known carnivores. A super carnivore (for lack of a better
name) that dines on other carnivores and herbivores would have an even
greater ?15N level.
So, ?15N pinpoints us on the food chain while ?13C tells us whether
the protein we eat is surf or turf or both.
Now that we have a full understanding of the ?magic phone booth? of
stable isotope analysis, let?s take a look at what the data show.
The data taken as a whole show the following:
Early man was a high-level carnivore. (As was his distant relative the
Neanderthal, who lived contemporaneously with ancient man in Europe.)
A higher-level carnivore, in fact, than foxes, wolves and other known
carnivores. The earliest anatomically modern humans got most of their
protein from animals of terrestrial origin. As time passed and the
populations of large game thinned due to heavy hunting by both humans
and Neanderthals, the human position on the food chain didn?t change,
but sources of protein changed from all terrestrial to more and more
marine (which includes fresh water fish, mussels, clams, etc., all of
which have a similar ?13C as animals from the ocean). Irrespective of
whether the protein came from the land or the sea, early man occupied
a super-carnivore niche in pre-agricultural days.
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