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Nutritional
Anthropology's Bible:
DEADLY
HARVEST
by
Geoff
Bond
COOKBOOK
Healthy
Harvest Information Page
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Chapter
4
The Science I—
Population Studies and Biochemical Clues
In the last chapter, we
thoroughly reviewed how we have arrived at our present food supply. We
often focus on the changes that have occurred in living memory and,
indeed, the pace of change has accelerated in just the last 50 years
However, our lengthy exploration demonstrates how, over a very long
period of time—more than 11,000 years—our food supply has been
steadily, subtly, and imperceptibly changing. We can see that the way we
eat today is radically different in nature from the way humans fed themselves for eons on the savannas of east
Africa
How much does this matter? In chapter 3, we outlined some of the
consequences of these differences but without going into detail. We will
now go into justifying these assertions based on scientific evidence. As
each piece of the jigsaw slots into place, we will see how this evidence
completes the gaps in the “Owner’s Manual.”
We begin by looking at
scientific studies on human populations around the globe and investigate
how their diets affect their health and life span. Such studies are
known as population studies, although scientists often use the term epidemiological studies. Then, we will look at the way our biochemistry is
supposed to work and what this tells us about the foods we should be
eating. In the next chapter, we examine the way nature has designed our
digestive system to work. Finally, we will look at what our modern diet
is doing to us. Along the way, we will discover insights to
thought-provoking conundrums such as how the Eskimo, with a massive
calcium intake, suffers from osteoporosis or how the long-lived and
healthy Okinawans nevertheless suffer unusually from senile dementia
POPULATION STUDY CLUES
Humans fanned out from Africa some 60,000 years ago until, by
15,000 years ago, they had ventured to all the major parts of the
planet. In this way, this tropical creature, Homo sapiens, now
lives in places that are not tropical. Moreover, these groups were
obliged to live on what was locally available, so humans all over the
planet were now consuming new foods in new ways.
Above Page 85
Today, the planet is like a huge laboratory with experiments
going on in different parts. It is an ideal opportunity to study
statistically how different lifestyles affect health and longevity. If a
scientific research institution were to propose such an experiment
today, the authorities would reject it as being cruel and unusual.
However, nature and history have combined to perform the experiment for
us, so we can learn from this wonderful resource. Let’s look at some
examples of interesting populations to see how their diet has changed
from the Savanna Model and the effect it has had on their health
Life Expectancy and “Health Expectancy”
A good starting point is to examine countrywide statistics for
death rates and the reasons for death. National governments collect these
figures and international bodies like the World Health Organization
collate them. Life expectancy is the factor that is most often paraded
as an indication of how well a country is doing. The figures most
bandied about are for life expectancy at birth. This means, on average, for
every baby born, the number of years it might be expected to live
In Pleistocene times, or even with the San, 30% of babies would die
within the first year. This drags down the averages for life expectancy at birth, particularly in the underdeveloped world. For this reason,
researchers often look at life expectancy at a later age, often at age
15. This gives the average number of years a 15-year-old is expected to
live. This produces some surprising and useful results: we find that
once an individual from a poor country has made it safely to 15 years
old, he or she can expect to live as long, or even longer, than their
counterparts in industrialized societies
For example, 15-year-old boys can expect to live to the age of 76.5 in
Japan, 75.6 in Greece, 75.3 in Hong Kong, but only 72.9 in the United
States [1]. Women live longer than men in all countries and the proportions
are similar: 15-year-old girls can expect to live to the age of 82.4 in
Japan, 80.9 in Hong Kong, 80.5 in Greece, but only 79.6 in the U.S. The
Japanese overall have the longest life expectancy in the world, closely
followed by people living in Hong Kong. Even
Vanishing Ways of Life
The interesting thing to note about life expectancy is that we do
not know how long someone will live until they die. Thus, life
expectancies are based on people who were born in the first decades of
the 20th century
and are now dying.
When we look at the life expectancy figures for 1990, those Chinese,
Greeks, Hong Kongers, and Americans lived the formative part of their
lives through the 1910s, 1920s and 1930s. Those old people have bodies
and habits that reflect their traditional ways of life. Nowadays, as
international lifestyles converge on the same eating pattern, we are
losing this valuable resource.
Page 86 above
if we take life expectancy at
birth, Chinese boys born in the Shanghai province have a life expectancy
of 75.7 years, while American boys at birth have a life expectancy of
71.8 [2]. Shanghai baby girls can expect to live for 79.2 years, but
American baby girls can only expect 78.6 years of life
The information gets even more interesting as we drill down to find out
what diseases are prevalent in a country and what diseases their
populations die of. Deliberately, we go back in time to sample the
conditions when people’s lifestyles were much more traditional. For
example, in 1960, for every 100,000 men, 466 Americans died of heart
disease, whereas only 48 Greeks died of it.
Greeks were five times more likely to die of a stroke than an Egyptian.
Britons were 1.5 times as likely to die of cancer as a Yugoslav [3]. In 1978, Norwegian women were five times more likely to suffer a
hip fracture than a Spanish woman [4]. In 1954, Japanese women had a
very low incidence of breast cancer— just 4 deaths per
10,000—compared to 18.5 deaths in the U.S.; an American man was 20
times more likely to die of prostate cancer than a Japanese man [5]. There is little correlation
between health and wealth. Japan and the U.S. are both rich countries,
but poor countries can be healthy too. In 1978, Albania was the poorest
country in Europe with an annual income of only $380 per person. In
spite of that, an Albanian man was half as likely to die of coronary
heart disease as a British man.[6]
There is another often-used measure of well-being known as
“health expectancy”—this is the number of years that a person can
expect to live “in full health.” Based on this measure, the Japanese
have the highest health expectancy of 74.5 years [7]. In comparison, the British come in 14th with 71.7
years and Americans come in 24th with only 70.0 years. In other words,
you die earlier and spend more time disabled (on average] if you are an
American
Statistics like this give us plenty to ponder. What is so special about
the Greeks, the Japanese, and the Hong Kong Chinese that they live
longer (and in better shape) than Americans? Why are some people more
vulnerable to cancers, heart disease, strokes, and osteoporosis than
others? There is now a mas-
Lifespan in Historical Times
There is a prevalent illusion that we live longer and better than
people in historical times. This is perhaps driven by our images of
life in the fetid cities so graphically described by Charles Dickens
and Victor Hugo. Sure, in those days, and in those places, life for
many people was indeed “mean, nasty, brutish and short” (to quote
the English enlightenment philosopher Thomas Hobbes). But that is
hardly a standard by which we should judge our prosperous and pampered
lives today. We have seen that rural Americans have much the same life
expectancy at 15 as did their great grandparents 150 years ago
Above Page 87
What about the prosperous and
pampered societies further back in time? It is a central thesis of
this book that neither the lifestyle of ancient agricultural
civilizations nor those of Medieval and Victorian Europe are a good
model for us today. Nevertheless, it helps to cast the spotlight on a
number of issues
After the farming revolution 10,000 years ago, for the first time in
the history of the human race, people were living in close proximity
with each other and they were dependent on farming. For the first
time, human populations were exposed to the hazards of crop failure,
new diseases—particularly new diseases— and disastrous floods and
plagues. Babies were born at more frequent intervals, but more babies
died in infancy. This drags down the averages. After a natural
disaster whole populations would be wiped out. The technology of
warfare became ever more murderous. But how are we to put on a
statistically sound basis a true estimate of longevity? The answer is
that we cannot
To get another bearing on the question, we can look at what the
ancient peoples themselves thought of their life expectancy. First, a
quick look at the writings of the ancient Greek, Homer. Based on
Homer’s directions in the Iliad, the archeologist Schlieman
discovered the site of Homer’s 3,000 year old Troy in 1870. It was a
dramatic vindication of the historical basis of Homer’s stories
about Odysseus. Homer relates how Odysseus’ wife Penelope remained
faithful even though he was absent for twenty years. The remarkable,
but little commented feature is that Penelope was besieged by ardent
suitors for the twenty years of Odysseus’ absence. Some of the
suitors were the same age as her son Telemachus. In other words, in
ancient Greece, 3,000 years ago, a 40- plus woman was such a
marriageable attraction that she was pursued by men half her age. Or
we can look at the words of Aristotle living in ancient Greece over
2,300 years ago. He recommended that men wait until they are 35 years
old before even getting married. The Greeks in general thought that a
man reached his peak at the age of 40. These are hardly the strategies
of people expecting a short life or a decrepit old age
Look again at some of Alexander the Great’s generals. Antigonus
Monophthalmos was a battling veteran who, encouraging his troops from
his war-horse, finally succumbed to a hail of javelins at the Battle
of Ipsus. He was 81 years old. His opponent, Lysimichos was later
killed at the Battle of Coropedium at the age of 79. His ally Selfcos
Nicator survived all battles only to be assassinated at the age of 78.
This is the other side of the coin, old men with a youth’s vigor.
Old men who could lead their troops into battle, wielding the heavy
armament of the period. Of course, this is all just circumstantial
evidence. Yet it is surely no coincidence that the ancient Greek diet
is still represented, 23 centuries later, by the much studied, and
healthful, Cretan diet that we discuss in a later segment.
Above Page 88
sive body of research to
identify how different populations’ lifestyles influence their life
and health expectancy. We will look at the knowledge obtained for a few
populations to see how the evidence builds up. To get the best contrast,
we have chosen some extreme cases
The Eskimos
As our species spread out
around the world, even the most inhospitable regions were settled. The
Eskimos were originally Siberians who got pushed across the Bering
Strait by population pressures. They arrived in Alaska 6,000 years ago
and found the land already occupied by the American Indians, who had
migrated there several thousand years earlier. The only available
territory was the land that the American Indians had shied away
from—the unimaginably difficult Arctic regions of Alaska and Canada
The Eskimos live in the most extreme of unfavorable environments. It is
either cool, cold, or extremely cold most of the time. However, they
have no biological special adaptation for these temperatures—the
Eskimos are still tropical creatures. They can only live inside the
Arctic Circle by insulating themselves from it. This was possible once
some Siberian ancestor had worked out how to kill and skin a large furry
animal and tailor it into a weather-tight garment. Like astronauts who
are obliged to wear spacesuits to work in the vacuum of outer space, so
the Eskimos have to cocoon themselves to live in the Arctic cold
The Eskimos’ main activity is hunting and traveling, but they also
spend quite a lot of time eating, sleeping, and loafing about [8]. In the depths of winter, just warming up the air they breathe
takes 1,000 calories. They eat much of their meat frozen, and that costs
their bodies another 300 calories just to thaw it out
Oxford University professor/explorer Hugh MacDonald Sinclair specialized
in studying the Eskimo diet, at a time when there were still many
Eskimos living the traditional way. In 1953, he estimated that, in
winter, the average Eskimo needs to consume about 4,500 calories per day
[9].
In Eskimo society, contrary to the Savanna Model,
hunting is not a luxury but a necessity. It is virtually the only source
of food—at no time is gathering an option as a mainstay. Men are still
the driving force in the hunt, although often the women come along and
help. Even so, in complete contrast to the Savanna Model, the women and
children are highly dependant on their men to feed them. The women are
occupied with the domestic chores of skinning the kill, preparing the
food, and making clothes and other artifacts
The Eskimo Diet
How did the Eskimos feed
themselves? Today, the Eskimo has the double-edged “benefit” of
modern civilization, so we have to go back to quite old studies,
archives, and records. Anne Keenleyside is a Canadian researcher with
special interest in paleopathology, the analysis of ancient bones. She
found that, with
Above Page 89
virtually no vegetation in their environment and winter temperatures
dropping to below –40°, the Eskimos had to rely almost entirely on
animal sources for their food [10]. Dr. Keenleyside and many other researchers have built up a
picture of the traditional Eskimo feeding pattern. Eskimos hunted fish,
seal, whale, walrus, musk ox, caribou, polar bears, wolves, birds,
rabbits, ducks, and geese. They ate every part of the animal—brains,
blood, intestines and even the feces. On occasion, the women would
gather eggs, crabs, mollusks, and shellfish
The Eskimos were particularly fond of the rather sour contents of the
caribou paunch. These are the partly digested remains of lichens and
mosses. They cut the blubber off the kill for use as lighting oil and
other external uses. They ate most animal food raw, sometimes after
considerable putrefaction. Other foods, particularly seal meat, were
eaten frozen. Some foods were lightly cooked over a seal-oil lamp or
boiled or roasted. Because the Eskimo lives above the tree line, a
campfire was a rare luxury fed by dried seaweed and other dried plant
remains [11]. In times of plenty, the Eskimo could consume prodigious amounts
of meat: 9 pounds in a day has been measured as a normal occurrence.
They drank prodigious amounts of water too (we will see why later when
we discuss acid/alkali balance)
It was only in the short summer that the Eskimo ate any plant food. The
treeless plains of the Arctic have a permanently frozen subsoil, known
as tundra, and no plants grow more than knee high. The women would
forage for berries, roots, stalks, buds, and leaves. They gathered some
kinds of algae and seaweed too. It is estimated, however, that plant
food represented no more than about 5% of the diet, even during the
growing season
The muscle meat of seal and whale shares similar characteristics with
our ancestral wild game—there is little “marbling,” or fat
permeating the muscle. The small amount of muscle fat and the visible
fat (blubber) are particularly rich in a essential fatty acids (EFAs),
notably one called eicosapentaenoic acid (EPA). Later in this chapter,
we’ll look at essential fatty acids and their significance to human
health
Dr. George Mann, in a report for the U.S. National Defense Committee in
1962, stated that by eating all the animal parts, the Eskimo obtained
enough of the “classic” micronutrients to survive including vitamin
C [12]. This might come as a surprise, since we think of vitamin C as
only coming from plants. However, the skin and guts of animals like seal
and caribou are also rich in this vitamin. On the other hand, the Eskimo
diet was very deficient in “background” micronutrients
Calcium consumption was huge—over 2,000 mg per day [13]. Protein intake was very high and the fat and oil intake was high
[14]. However, the types of fat are of key importance: the Eskimo diet
was very low in saturated fat, high in omega-3 oils, and quite high in
cholesterol; there were virtually no unhealthy trans fatty acids. The
Eskimos’ intake of fiber, carbohydrates, and sugars was
90 Deadly Harvest
almost nonexistent, although they got some glycogen (a kind of animal
carbohydrate) from the meat. Canadian researcher Kang-Jey Ho estimates
that 50% of energy came from fat, 35% from protein, and 15% from
glycogen [15]. Most notably, there was virtually no plant food, no soluble
fiber, nor the myriad of micronutrients that only plant foods can
provide
Eskimo Health
The Eskimos first attracted
attention because of an anomaly: in spite of their high-fat, high-meat
diet, they had no cardiovascular disease, thromboses, or strokes; they
had low blood pressure and good cholesterol levels [16].
In fact, it was too much of a good thing. Their
blood was slow to clot when needed (known as a prolonged “bleeding
time”) and they suffered from difficult-to-stop nosebleeds
These discoveries led researchers to find the vital role of the various
fatty acids in manipulating body biochemistry. The Eskimos did not
suffer from vitamin C deficiency (scurvy) or from vitamin D deficiency
(rickets); nor did they suffer from diabetes, appendicitis, arthritis,
cancer, or dental caries (cavities)
On the other hand, the Eskimo aged fast: they became wizened and
shriveled so that a 50-year-old looked more like an 80-year-old. It is
estimated that the average life span was indeed only about 50 years. We
can learn something too from their high calcium intake of up to 2,000 mg
per day. In spite of this megadose of calcium, the Eskimos suffered from
bone demineralization and osteoporosis [17]. Doesn’t this go against all we are told today? This should make
us question a major nutritional doctrine—that we have only to swallow
calcium by the bucketful to avoid osteoporosis. In fact, good bone
health is a very complex matter, easily upset by a myriad of lifestyle
factors, of which calcium intake is almost irrelevant. We will see later
the chief factor at the root of Eskimo osteoporosis and the lessons it
gives us for the Savanna Model
Today, the Eskimos suffer the same fate as other hunter-gatherers who
adopt the Western lifestyle: high rates of obesity, heart disease,
diabetes, and high mortality. Life expectancy has dropped even lower.
Later, we will refer back to these observations to learn how the Eskimo
had remarkably good health in some areas and weakness in others
The Japanese
We are all familiar with the
so-called staple of the Japanese diet, rice. We say “so-called”
because there are two misconceptions about rice. First, the Japanese did
not eat that much of it—even as recently as 1998, daily consumption of
rice was just 6 ounces. And although rice retains a hallowed place in
Japanese hearts, it is regarded as a poor man’s food to be replaced by
plant foods whenever possible [18]. Traditionally, the Japanese are Buddhists and, as
such, they did not eat animals at all. However, they did eat fish, often
raw. By Western standards, it was The Science I 91 a high consumption, around 90 g (3.15 ounces) per person per day
(four times as much as the average American). From this, they got a high
consumption of fish oil, notably the essential fatty acid
eicosapentaenoic acid (EPA). Even so, their overall consumption of fat
was very low—no more than 10% of calories— which is much lower than
the U.S. Department of Agriculture recommended (but rarely achieved)
maximum of 30%
The largest percentage of their fat came from rapeseed (canola) oil.
East Asians have cultivated rapeseed for millennia, and the Japanese
have used rapeseed oil in frugal amounts for at least 2,000 years. To a
lesser extent, they used soybean oil. Consumption of saturated fats,
hydrogenated fats, and trans-fatty acids was almost zero
The idea of dairy farming had never reached Japan and dairy products
never formed part of their traditional diet. Rice was the staple and
other cereals were virtually unknown. The Japanese traditionally did not
eat wheat, barley, rye, or oats. And they did not eat potatoes either.
So, when we say that Japanese consumption of rice was 6 ounces per day,
that is it: no other carbohydrate fillers such as bread, pasta, pizza,
or french fries existed in their diet
The Japanese traditionally had to husband their resources and they ate
much more sparingly than is our custom in the West. They had a high
consumption of salt (from soy sauce) of 14 g per person per day. This is
a great deal worse than government recommendations of 8 g per day
maximum. The Japanese also smoke a lot: 70% of men and 45% of women
smoke some form of tobacco
Japanese Longevity and Health
Japanese men have a life
expectancy four years greater than Americans and their health expectancy
is 4.5 years longer than Americans. But studies show that this only
applies as long as the Japanese stay in Japan. When Japanese migrate to
America and adopt the American way of life, including its diet, their
life expectancy drops to the American norm and they get the same
diseases [19]. This suggests that Japanese
health and longevity are not about genes but about the way the Japanese
live their lives, notably the foods they eat and do not eat
At home, by a fluke of culture, geography, and luck, the Japanese have
hit on a good lifestyle, but even so, it is not perfect. For example,
they smoke too much and they consume too much salt. More than in most
other countries, the Japanese die of strokes and heart disease. The diet
of raw fish means that they absorb the live eggs and larvae of
intestinal parasites, so that worm infestations of the gut, virtually
unknown in the West, are quite common in Japan
Within the general statistics for Japan are buried even more startling
results. The archipelago of Okinawa is remote from the Japanese mainland
and its population has an even more enviable record for health and
longevity. They have one of the highest proportion of centenarians in
the world: their chances of living to 100 are 12 times those of an
American
Above Page 92
A study carried out in the
remote and tiny Okinawan island of Kohama found that the inhabitants eat
even more fish, 144 g (about 5 ounces), and far less salt, about 6 g,
per day [20]. They eat seaweed and herbaceous plants and also sweet potato and
tofu (soybean curd). They have adopted some Chinese practices from
nearby Taiwan, eating some pork and drinking green tea. And they
exercise a lot: 95% of the 80-year-olds studied led active lives,
working long hours every day in their fish-farming paddies
The Okinawans are a poor people, but even the poorest precinct has
better longevity—two years more—than the already stellar performance
of Japan as a whole [21]. They have the lowest incidence of cardiovascular disease in all
of Japan, even though they smoke the same amount. At age 59, only 8% of
the population had high blood pressure, 2.3% had heart disease, and 1.2%
had diabetes
These figures are two to three times better than mainland Japan.
However, the Okinawans had double the incidence of senile dementia (later, we will
find the explanation for this interesting result). In a study of
80-year-olds, 90% were fully functional human beings without any
disability; only three had impaired hearing and only four had fading
eyesight [22].
The remarkable health and
longevity of the Okinawans has generated a number of diet programs.
However, as we shall see, it is still not ideal. How do we interpret the
eating patterns of a poor, agro-fishing Japanese community? Do the types
of fish make a difference? Is the green tea significant? Is their
“sweet potato” like our sweet potato and does it matter? As we will
see later, these matters have a prime importance
The Cretans
Similar observations have been made with the peoples of the
Mediterranean northern rim. The people of the Greek island of Crete had
one of the highest life expectancies in the world, in spite of a hard
lifestyle. Indeed, although half a world away, there are many
similarities with the Okinawan way of life. The Cretans ate frugally;
they ate fish but virtually no meat (just the occasional goat’s meat,
as beef was nonexistent); they ate plenty of plant food (notably an
unusual salad-green called purslane); and they consumed very little
dairy, pastries, or sugars
Unlike the Okinawans, they ate bread—a rough-ground, whole-wheat
variety— and they had a moderate fat consumption through the sparing
use of olive oil in the kitchen. They also had an extraordinary custom:
for the Cretan, traditional breakfast often consisted of a jigger of
olive oil downed in one gulp, and that was it until lunchtime. Wine was
also commonly drunk but in moderation
These people were poor and complained that they felt hungry most of the
time. They were obliged to be physically active on their land until an
advanced age. Yet, the Cretans had the longest life span in Europe and
their incidence of heart disease, colon cancer, high blood pressure,
osteoporosis, and diabetes are all much lower than the peoples of
northern Europe and North America
Above Page 93
American researcher Ancel Keys, who first investigated the fabled
Cretan longevity and health in the 1950s, wrote a book about his
findings which became popular as the so-called Mediterranean diet [23] But this Mediterranean diet has nothing in common with the kind
of meal you will find in an Italian, Spanish, or French restaurant. It
contains no spaghetti, paella, pizza, or blanquette de veau; even less
does it contain their rich cheeses and cream sauces
With the advance of prosperity and the crumbling of old traditions, the
Cretans are now adopting Western eating habits, and their deterioration
in health is being documented
Testing the Cretan Diet
In the meantime, the baton
has passed to researchers who investigated the Mediterranean diet with
well-controlled clinical trials. These trials are studies where large
groups of people are divided into two test groups. One group is the
“experimental” group: they are given the new diet to eat over
several years. The second group is the “control” group: they
continue to eat their normal diet. At the beginning of the study, both
groups are tested for various health indicators, such as blood pressure,
cholesterol levels, weight, and so on. They are then retested at
intervals as time goes by. Often these studies go on for five or ten
years, during which there will also be some deaths
Thousands of clinical trials have tested various hypotheses about food
and how it affects health and life span. The results of such studies
give us very clear indications as to what is right for human beings to
eat and what is not. Quite understandably, we have not the space here to
go into the detail of all these studies. We will therefore cite one
powerful example and then give a summary of the overall picture that the
collection of studies paints for us.
Under chief researcher Serge Renaud, the Lyon Diet Heart Study involved
a group of 606 heart attack patients living in Lyon, France. It was
equally divided into a control group and an experimental group [24]. The control group followed
the conventional advice of the hospital dietitians based on the American
Heart Association (AHA) diet. The experimental group was told to adopt a
Cretan type diet: more green vegetables and root vegetables, more fish,
less meat, and replace beef, pork, and lamb with poultry, no day without
fruit, and replace butter and cream with a special margarine made from
canola (rapeseed) oil. Olive oil and/or canola oil replaced all other
fats. Moderate wine consumption was allowed.
After 27 months, the experiment was stopped early: members of the
control group on the AHA diet were dying at a much faster rate than
those on the Cretan diet. There were 16 deaths on the AHA diet compared
to just three on the Cretan diet. The AHA group was also suffering a
much higher rate of second heart attacks: they had 17 non-fatal heart
attacks compared to just five on the Cretan diet.
Above Page 94
The French Paradox
In most countries where the
population has a high intake of saturated fat, there is a
corresponding high death rate from heart disease. However, the
situation in France does not conform to this pattern. The French have
a high intake of saturated fat, particularly in cheese where they
consume three times as much as Americans, but they have a low death
rate from heart disease. It is the so-called French paradox.
Professor Serge Renaud dug deeper and found that there were strong
regional differences. In Toulouse, in the southwest of France, a
Mediterranean-type diet was practised. While not consuming much olive
oil, the Toulousains did use duck and goose fat rather than butter. He
found that they drank red wine copiously— up to one bottle per
person per day (it is the Bordeaux region after all). In contrast, in
the northern city of Strasbourg, on the border with Germany, the diet
is more “Anglo-Saxon”: the population drank much more milk, used
butter for everything, and drank beer rather than wine.
In comparison with the United States, Dr. Renaud found that the
pattern of French alcohol consumption was quite different. For the
French, wine is 58% of alcohol consumption (in the U.S., 11%), beer
23% (U.S., 57%), spirits 19% (U.S., 37%). Plus, the French mostly
consume their wine as an agreeable accompaniment to a meal, whereas in
many other countries binge drinking is common and alcohol is consumed
in order to get drunk.
Paradoxes like this are useful tools to identify such mysterious
factors. They are the clues we need in order to understand what really
makes our bodies work properly. Paradoxes also remind us that nothing
is as simple as it seems: that, in matters like health and nutrition,
there is rarely a straight line from cause to effect. We will see
later how the French paradox might be explained and how it gives us
more clues about our ancestral, naturally adapted diet.
It is not as though the AHA
diet was bad—it was certainly better than how the patients were eating
before the start of the study—but the Cretan diet proved to be
exceptionally superior even to the conventional dietary treatment
recommended by the American Heart Association. The committee charged
with looking after the welfare of the groups swiftly decided to stop the
trial early so that the AHA group of patients could benefit from the
study’s insights and adopt the Cretan diet if they so desired.
Summary—Population Study Clues
Researchers have carried out
thousands of similar clinical studies on a huge range of different
dietary factors. It is an exciting story in itself, but it is not the
Above Page 95
purpose of this book to
relate them in detail. However, the results of such studies do fill in
some important gaps in the “Owner’s Manual.” To save the reader so
much detail then, we distill these results into generalized summaries.
They highlight the foods linked to disease and the foods linked to
health. This is a broad-brush approach, but the circumstantial evidence
is pointing strongly to lifestyle patterns close to our ancestral,
naturally adapted ones. In order to live in the modern world, we need to
understand what to make of this evidence, which is the purpose of the
latter part of the book.
HELPFUL FOODS
Helpful
Foods
|
Foods
|
Diseases
Encouraged
|
Diseases
Inhibited
|
Fruit
Non-starchy vegetables
Salads
Tubers (non-starchy)
Berries
Nuts (in moderation)
Seafood and oily fish (in moderation)
Wild animal protein (in moderation)
Low-fat poultry (in moderation) |
None
|
Arthritis
Bowel diseases
Cancers
Constipation
Diabetes
Heart disease
High blood pressure
Indigestion
Infectious diseases
Obesity
Osteoporosis |
Harmful
Foods
|
Foods
|
Diseases
Inhibited
|
Diseases
Encouraged
|
Bulk
vegetable oils
Dairy products
Farmed “red” meat
Grains
Saturated fats
Hydrogenated fats
Trans-fats
Sugars
Starchy vegetables
Meat (high-meat diet)
|
None
|
Allergies
Autoimmune diseases Cancers
Constipation
Heart disease
High blood pressure
Indigestion
Infectious diseases
Obesity
Osteoporosis
Stroke |
BIOCHEMICAL CLUES
We turn now to the study of
the tens of thousands of chemicals that swirl around our bodies. It is
also the study of how they are orchestrated into this incredibly complex
system that, day after day, makes our bodies function. It is the science
known as biochemistry. A knowledge of how human biochemistry operates
will provide us with valuable clues as to what dietary factors fuel the
system as nature designed it.
With advancing research, we are realizing just how incredibly complex
are the workings of the body. It is a classic case of the more we know,
the more we realize how little we know. Biochemists call our body’s
biochemistry a “chaotic” system in the mathematical sense. That is,
it obeys all physical laws, yet the outcome of any particular action is
mathematically impossible to predict. The weather is another chaotic
system—even if we knew everything about barometric pressure,
temperature, and so forth, there is no way of accurately predicting the
weather. We now understand that, when we try to intervene in our
body’s operations, we can never predict the outcome with certainty
either.
There is a myriad of chemical processes going on in the body all the
time. It is mind-bogglingly complex, like a three-dimensional chess
game. We have to just understand that it is an unmanageable network. A
very important lesson is this: an action today will sometimes have the
opposite outcome to the same action yesterday; it all depends on what
other processes are happening in the body at the same time.
To take one example: a teaspoon of evening primrose oil taken yesterday
might calm inflamed joints; today, it might make them worse. What causes
this disquietingly unpredictable result? It all depends on what else you
have eaten in the last few hours. A glycemic food (one that causes blood
sugar to spike abnormally) increases the body’s production of an
enzyme called delta-5-desaturase.
This in turn flips a switch: evening primrose oil now makes chemicals
that inflame joints rather than calm them. This is just one of a huge
variety of inputs for which we cannot second-guess the outcome.
Indeed, this is one of our central messages: we cannot micromanage our
body’s operations. However, this is what people are trying to do all
the time, and we end up driving a truck through the delicate minuet
being danced by our body’s biochemistry. We meddle in things we only
partly understand with consequences that can be the opposite of those
intended. I call it the Sorcerer’s Apprentice syndrome. In the 1940
Disney film Fantasia, Mickey
Mouse knows the magic spell to animate the broom to fetch water from the
well to fill up the kitchen sink. However, he doesn’t know the magic
spell to make the broom stop fetching water. Result? The broom goes out
of control filling up first the sink and then the house with a
nightmarish, unstoppable flood of water. The lesson to learn is this:
our own body is the best manager of itself—we just have to get out of
the way and give it the tools to do the job.
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Below:
Page 98
We have known for a long time
that some saturated fats are harmful to the smooth functioning of our
bodies. Already, the message has gotten through that old friends like
cream, butter, and fatty meat are not to be trusted. Health
professionals have been proclaiming for decades that we should avoid
them. Recent discoveries are dispelling other myths: cholesterol
consumption of itself is not threatening to health; cholesterol only
becomes a problem when it attaches itself to the artery walls. Why does
it do that? One immediate reason is that immune system cells on one side
of the wall are trying to pull the cholesterol molecule through from the
other side, and it gets stuck. The question is: what provokes immune
cells into doing something harmful like that?
In other words, our biochemistry needs to work to a very specific
pattern. It has firmly defined characteristics that provide strong clues
to our naturally adapted diet. We will now examine four of them to see
how they illuminate our understanding of the “Owner’s Manual”:
blood sugar control, essential fatty acid hormones, the salt/potassium
ratio, and the acid/alkali balance.
Blood Sugar Control and Carbohydrates
People generally understand that carbohydrates are starchy foods
like bread, pasta, potatoes, cookies, and cereals. Technically, however,
the term carbohydrate is much broader: it also includes a whole spectrum
of vegetation (such as lettuce, broccoli, and apples) to starches and
sugars (such as sugar itself, honey, confectionary, and maple syrup). In
fact, carbohydrate molecules are nothing more than glucose molecules
strung together in a multitude of different ways.
Most creatures, even carnivores like dogs, are equipped to digest sugars
and starches. Our bodies can unzip the starch molecule back into glucose
molecules very quickly by using special helpers known as enzymes.
Enzymes have the power of speeding up chemical reactions by thousands of
times. Other carbohydrates, such as the material that makes plant walls,
can take much longer to digest—these are known as “very complex
carbohydrates.”
What are Carbohydrates?
Carbohydrates used to be
classed as either simple or complex. Simple carbohydrates were sugars
and were considered “bad” for blood sugar control. Complex
carbohydrates included everything else from starches to broccoli and
were all considered “good” since they were thought to be easier on
blood sugar control.
We now realize that this was too simplistic, because starches aren’t
all that complex either and are “bad” as well. In common parlance,
starches are still called complex carbohydrates; however, a new
category of “very complex carbohydrates” has been created for
foods such as broccoli, lettuce, and so on, and these now inherit the
mantle of “good” carbohydrates.
Above: Page 98
The body converts all
carbohydrates, sometimes quickly and sometimes slowly (according to
their type), into sugar (glucose) in the bloodstream. The body needs to
maintain blood glucose levels within very narrow limits, which it does
by a seesaw mechanism using hormones released by the pancreas. The
pancreas is an organ that has many functions: it secretes a wide variety
of hormones and digestive enzymes under instruction from other parts of
the body.
If blood sugar is low, the brain instructs the pancreas to release the
hormone glucagon into the blood. Glucagon is an “unlocking hormone”
that instructs the fat cells to release fat, convert it into glucose,
and push it into the bloodstream.
In contrast, if the glucose level is too high, the brain instructs the
pancreas to release the hormone insulin into the blood. Insulin is a
‘locking up’ hormone that instructs the fat cells to take the excess
blood glucose and store it as fat. In other words, excess glucose equals
excess body fat.
In a normal glucose reaction, the body carefully masters the rising
level of glucose in the blood and brings it under control. There is no
abnormal peak of glucose and the level never drops below the normal
fasting level. In a bad reaction, we eat a food that gives us a “sugar
rush.” The arrival of glucose is too rapid, and the pancreas cannot
maintain this orderly processing. Instead, glucose levels spike sharply
to overdose levels about 20 to 30 minutes after eating the food. This
condition is known as hyperglycemia, and when this happens, nerve
endings are killed off and blood vessels are damaged.
The state of hyperglycemia lasts about 30 minutes, during which we do
not feel anything special, and then the pancreas catches up. But it
overshoots the mark—the pancreas overcompensates and clears too much
glucose from the bloodstream. By 2 to 3 hours after eating the food,
there is now a deficiency of glucose in the blood. This deficiency,
known as hypoglycemia, provokes feelings of drowsiness, dizziness,
irritability, exhaustion, cold sweats, depression, headaches, and a
desperate craving for something sugary. Many readers will be familiar
with this phenomenon: the mid-morning or mid-afternoon “slump,”
which happens a couple of hours after a copious bad-carbohydrate meal.
In this way, abnormally high blood sugar levels mean abnormally high
insulin levels. Most Americans are putting their bodies under this kind
of stress on a daily basis. This is a biochemical disaster: insulin is a
powerful hormone and having it floating around in abnormal quantities (hyperinsulinemia)
upsets all other kinds of hormonal reactions.
For example, insulin instructs the liver to make cholesterol. The more
abnormal the insulin level, the more abnormal the cholesterol
production. The reason most people have high cholesterol levels is not
because they are eating it, but because their body is making abnormal
quantities of it. In a similar way, abnormal insulin levels provoke
abnormal levels of other hormones, which cause abnormal blood clotting
(leading to strokes and thrombosis), abnormal clogging and inflammation
of arteries, abnormal suppression of the immune
Above Page 99
system (allowing cancers to
grow), and even increased sensitivity to arthritis, allergies, and
asthma. The problem with hyperinsulinemia is that you do not even feel
it. It goes about its work silently and you notice nothing until it is
too late—you have the stroke, the heart attack, the cancer, and the
sludged arteries. The end result of this abuse of the blood sugar
mechanism is often diabetes.
Diabetes is a condition in which one of two things happens: either the
pancreas cannot keep up with the demand for insulin and so the insulin
production machinery goes into failure or the fat cells stop listening
to insulin’s instructions and fail to absorb sugar out of the
bloodstream. Either way, there is then an excess concentration of sugar
in the blood. Diabetes sufferers, even if medicated, are vulnerable to
heart disease, kidney failure, blindness, and gangrene in the feet and
hands.
Sugar for Fat Equals Fat
Americans now worry about fat
in the diet and seek out fat-free and low-fat foods. The food
manufacturers have been only too happy to oblige. But almost always in
such foods, they have increased the sugar content to compensate.
Unfortunately, fat-free but sugary foods can be just as fattening. But
the hormone insulin is then released to take the excess blood sugar
and store it as fat. This insulin mechanism is the major reason why
Americans are still getting fatter, even if they are trying to reduce
their fat intake. Of course, when they eat fat, insulin sweeps that
into the fat cells too.
This illustrates another curiosity of human biochemistry—fat by
itself does not increase insulin levels. Therefore, fat eaten in the
absence of either carbohydrates or protein is not easily absorbed into
the fat cells. This explains how the Cretans could consume a jigger of
olive oil on an empty stomach and not get fat.
Think of abnormal insulin levels like the iceberg that sank the Titanic.
You see very little on the surface, but underneath lurks danger. You
just see apparently disconnected peaks—heart disease, thrombosis,
artery disease, cancer, allergies, depression, arthritis, obesity—but
a looming mass of ice (representing abnormal insulin levels)
interconnects them under the surface.
Glycemic Index and Glycemic Load
Until the 1980s, medical knowledge about how diet affects and
controls diabetes was surprisingly imperfect. Then, Canadian researcher
David Jenkins developed a breakthrough concept—the glycemic index [25]. He fed various foods to volunteers and measured their blood sugar
over a period of time, usually two hours. He then did the same with
glucose. Blood sugar is, in fact, glucose and so glucose is thought to
be the most “glycemic,” that is, it creates the most powerful sugar
rush. Jenkins compared the spikes in blood glucose caused by the test
Above Page 100
foods against the spike for
glucose, and the ratio of the two, on a scale of 0 to 100, gives the
glycemic index.
The results surprised him and surprised those doctors who took notice.
This new way of looking at what carbohydrates do to blood sugar control
turned conventional medical ideas upside down. A whole range of foods
that doctors thought safe, particularly for diabetics, Jenkins found to
be decidedly dubious.
Over the years, researchers have tested many more foods and they found
that most processed foods have consistently the same index. However,
fresh fruits and vegetables, which are naturally variable, can have
quite a wide range of index.
Even so, when all is considered, the glycemic index measure brings
completely new insights into what type of foods are right for humans: we
now understand that nature did not design the human body to handle foods
that give a blood sugar rush.
In this book, foods that have an index in the range of 61 and above, we
call “bad” carbohydrates: they consistently produce an unhealthy
sugar spike.
Foods with an index between 31 and 60, we call “borderline”
carbohydrates: they produce sugar surges which, in a healthy person, the
body controls, but only at the price of unnecessary stress to the body.
Foods with an index from 0 to 30, we call “favorable” carbohydrates:
they produce blood sugar levels that are within the body’s normal
range for comfortable, unstressed handling.
Food
|
Glycemic
Index
(glucose
= 100)
|
Category
|
Maltose
|
110
|
Bad
|
Cornflakes
|
85
|
Bad
|
Potato,
baked
|
85
|
Bad
|
Bread,
whole-wheat
|
70
|
Bad
|
Sugar
|
65
|
Bad
|
Pineapple
|
65
|
Bad
|
Rice,
brown
|
55
|
Borderline
|
Spaghetti
|
45
|
Borderline
|
Banana
(unripe)
|
40
|
Borderline
|
Raspberries
|
25
|
Favorable
|
Fructose
|
20
|
Favorable
|
Walnuts
|
15
|
Favorable
|
Tomato
|
15
|
Favorable
|
Lettuce
|
15
|
Favorable
|
CAL GLYCEMIC INDEX
Above Page 101
Glycemic index scores present
a few surprises. Starchy foods like bread (even whole-wheat) and
breakfast cereal (corn flakes) are “bad” carbohydrates.
Fruits are all over the place: pineapple is “bad,” banana is
“borderline,” and raspberries are “favorable.” Unsurprisingly,
non-starchy, non-sugary foods like most nuts, salads, and vegetables fit
into the “favorable” category.
Another surprise is the special type of sugar called fructose—it has a
favorable glycemic index and does not raise blood sugar levels
unhealthily. Fructose is common in fruit, so it is not a surprise that
human bodies are very well adapted to it. Fructose is not converted to
glucose straight away by the digestive system; it has to pass through
the liver for conversion. This slows down the rate at which it hits the
bloodstream. Finally, it’s a surprise to find another sugar, maltose,
that is more glycemic than glucose itself. Maltose is made of two
glucose molecules joined together and, as its name suggests, is the
chief sugar in malt.
There is another factor that makes a difference: the concentration of
sugars and starches in the particular food. Will just one cornflake or
one pineapple chunk set off a bad glycemic reaction? One supposes not,
but to find out, some researchers have developed the concept of the
“glycemic load.” This is an attempt to define how much of a food
needs to be consumed before it triggers a glycemic reaction. They take
the glycemic index (GI) of a food and combine it with the amount of
carbohydrate in a standard U.S. Department of Agriculture (USDA) serving
size to get the glycemic load (GL) score. A GL of 20 or more is
“high,” a GL of 11 to 19 is “medium,” and a GL of 10 or less is
“low.”
Of course, everything depends on the serving size that is actually
consumed by a person. That is why even the concept of glycemic load has
its limitations— this factor is only valid if one consumes a standard
serving size. The USDA sometimes has absurdly low “normal” serving
sizes. For example, a serving of spaghetti is 2 ounces (57 g) of dry
weight. Most home cooks use double that quantity when serving spaghetti.
Insulin Index
Measuring the glycemic power
of foods is a useful guide and it has a direct bearing on the damage
that glucose can do to our health. Nevertheless, it is one stage removed
from a worse villain: abnormally high insulin levels. Because of
insulin’s potential for creating havoc with our biochemistry,
researchers such as human nutrition expert Susanna H. Holt have
established insulin indexes for many foods [26]. She did it in a way similar to the process for glycemic indexes:
volunteers ate different foods and had their insulin levels measured
over several hours.
Insulin indexes usually, but not always, rise and fall in the same
rhythm with the glycemic index. Once again, there are some real
surprises—some foods that might pass muster on a glycemic basis fail
on an insulinemic basis. There is one further factor: proteins might not
raise blood sugar levels, but they do raise insulin levels, some very sharply—notably, yogurt. Worse,
if proteins and car-
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Below Page 103
bohydrates are eaten
together, then the insulin raising power of the combination is much
greater than of the two ingredients separately.
The table gives some typical values for an insulin index [27]. It can be seen that potato and yogurt are exceptionally
“insulinemic”—that is, they have a powerful insulin-raising
ability. Beef, fish, and eggs have a normal insulin-raising ability.
Information like this helps build a picture of the foods that we should
consider eliminating from the Savanna Model candidates.
Food
|
Index
|
Category
|
Potatoes
|
124
|
Abnormal
|
Yogurt
|
115
|
Abnormal
|
Bread
|
10
|
Abnormal
|
Rice
|
79
|
Abnormal
|
Fish
|
59
|
Normal
|
Beef
|
51
|
Normal
|
Eggs
|
31
|
Normal
|
We’re Not Designed to Consume Sugars
We saw in chapter 1 how the San
were measured as having a low “insulin response”: this means that
their fat cells do not react quickly to the instructions given by
insulin. Another way of saying it is that their bodies display
“insulin resistance.” Insulin resistance occurs when the body needs
to produce “abnormal” levels of insulin to deal with high-glycemic
foods. Australian professor Janette Brand-Miller is the icon of glycemic
index research. She and Stephen Colagiuri of the University of Sydney,
Australia, argue that insulin resistance is actually the naturally
adapted state for human beings [28]. All peoples used to living on a primitive diet, such
as the Australian Aboriginal, the Native American, and the African
Pygmy, all display insulin resistance. This is normal, since the
forager’s food supply does not contain glycemic foods.
In fact, this insulin resistance is helpful for reproduction. During
pregnancy, glucose needs to be diverted to the fetus. Insulin-resistant
females automatically maintain glucose in circulation so that the fetus
can benefit from it, rather than locking it up in her own fat stores.
Furthermore, during breastfeeding, the breasts develop insulin
sensitivity, which encourages the uptake, by breast tissue, of glucose
for conversion into the milk sugar lactose.
Most primal peoples are terribly vulnerable to the Western diet and
rapidly develop diabetes, obesity, and heart disease. In a classic
study, Australian
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Below Page 104
researcher Kerin O’Dea
returned diabetic Aboriginals to their traditional lifestyle [29]. Just a few weeks of living like this brought their diabetes,
obesity, and poor cardiovascular vital signs back to normal.
The research on blood sugar control and insulin resistance provides
powerful insights into the naturally adapted diet for humans. Clearly,
nature did not design us to consume sugars and starches. This is a
startling revelation for we are so used to the idea that starchy foods,
such as grains and potatoes, should be part of the diet. We also see
that not all fruits are entirely innocent: some of today’s fruits
clearly conform to our ancestral diet and some do not. It’s clear that
we have to look past the stereotypes, and at the details about what we
eat, in order to understand how to navigate through our food options.
Fats and Oils
Fats and oils (“oils” are
fats that are liquid at room temperature) were divided into three types:
saturated, monounsaturated, and polyunsaturated. All three types are
made up of fatty acids, the building blocks of all fats. Primal humans
subsist on a very low-fat diet. Even so, human nutrition requires a fat
intake of some kind, because the body sickens and dies if certain fatty
acids are not in the diet. These are known as essential fatty acids (EFAs),
and all are polyunsaturated fats. This family can be divided into two
classes called omega-3s and omega-6s.
Omega-3 EFAs are found in plants and animal matter. In plants, the most
common form is alpha-linolenic acid (ALA), found particularly in
walnuts, flaxseed, hempseed, and rapeseed (canola oil). In animals,
omega-3 oils are particularly found in “oily” fish, such as
sardines, salmon, trout, and tuna. The most common omega-3 EFAs in fish
are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Omega-6
EFAs are chiefly found in oilseed plants: for example, corn oil,
sunflower oil, safflower oil, peanut oil, and soybean oil. There is only
one, main omega-6 which is called linoleic acid (LA).
The body only needs these two classes of fat in small quantities of a
gram or two (about 1/2
tsp) from all food sources combined per day. They
are important because they act rather like vitamins. Indeed, at one
time, we called them vitamin F1 and F2—it is a pity that we dropped
this designation, because it gives us an idea of their powerful effect
on the body. The body converts these EFAs into potent types of hormones
called prostaglandins. Prostaglandins are powerful agents that cause the
body to do things like thicken or thin blood, increase or decrease bone
building, depress or boost the immune system, and a host of other
effects.
The first important feature is that what one omega type of EFA does, the
other omega type does the opposite. Plus, they both use the same
biochemical machinery to do their work. If one is using it, the other
cannot; that is, one of them can monopolize the process to the complete
exclusion of the other. This leads to a third important feature: they
need to be present in the diet in a pro-
Above Page 104
portion of about 1 to
1—they need to be balanced. If not, one of them dominates and produces
prostaglandins that, in abnormal quantities, cause sickness and disease.
In the American diet, this is indeed the case. It is estimated that the
ratio of omega-6s to omega-3s is about 32 to 1 instead of the ideal 1 to
1. These abnormal quantities of omega-6 fatty acids produce volumes of
“bad prostaglandins” that are in part responsible for many of the
diseases we see today.
Fatty Acids and the Ancestral Diet
Earlier in this chapter, we
touched on this subject with the Eskimo. The Eskimo diet is overbalanced
in favor of the omega-3 oils, the opposite to that of the western diet.
This causes overproduction of compounds that abnormally reduce blood platelet stickiness and blood clotting, which explains the
Eskimo’s unstoppable nosebleeds and immunity to heart disease.
However, most people in the West have the opposite problem: they have
sticky blood liable to clot when it is not supposed to. This phenomenon
can lull Western surgeons into a false sense of security—they find
that bleeding is easily controlled. Steven Gundry, medical director of
the International Heart Institute, in Palm Springs, relates how American
surgeons could not understand the difficulty that Japanese surgeons had
in controlling bleeding under the surgeon’s knife [30]. Belatedly, they realized that this is the normal condition for
Above Page 105
Diseases Provoked by
Bad Prostaglandins
Bad prostaglandins increase:
• Blood clotting (thrombosis)
• Bone destruction (osteoporosis)
• Inflammation (arthritis)
• Histamines (allergies)
• Pain sensitivity
• Vasoconstriction (high blood pressure)
• Autoimmune reactions (arthritis, lupus,
multiple sclerosis)
• Hypertension (high blood pressure)
• Bronchial restriction (asthma)
Bad prostaglandins
depress:
• Immune system (cancer)
• Bone building (osteoporosis)
healthy people: the Japanese, with their diet rich in oily fish,
have the omega- 3/omega-6 balance about right.
How does this fit in with what we know about essential fatty acids in
our ancestral diet? The vegetation was indeed rich in these fatty acids.
In turn, the creatures such as antelope that ate the vegetation, and the
animals (such as lions) that ate the antelope, were all rich in these
fatty acids. Even more remarkable, the omega-3 and omega-6 fatty acids
were present in a ratio of around 1 to 1. In fact, we should not be
surprised that these fatty acids are essential—our bodies never had to learn how to make them, just like our
bodies have lost the ability to make vitamin C because it was always
present in our diets of fruits and plants. Carnivores, such as lions,
cheetahs, and cats do not eat fruits and plants and so their bodies make
their own vitamin C. In contrast, carnivores are dependent on a wider
range of fatty acids in their diet [31].
Companion animal researcher
Michael G Hayek points out that cats, for example, cannot transform
alpha-linolenic acid (usually from plants) into another essential
compound, arachidonic acid (AA) [32]. Cats get a wide range of necessary fatty acids
from their prey, such as arachidonic acid (AA), gamma-linoleic acid (GLA),
and eicosapentaenoic acid (EPA). Plants do not have them. This is
another sign that hunted meat could not have formed a significant part
of the human diet, otherwise, as with cats, our bodies would have lost
the ability to make these fatty acids.
A large number of favorable factors must come together for humans to
have evolved as they did. Humans are peculiar because of their large
brains, so one of those factors must have been an abundant supply of
brain-building material.
Two polyunsaturated fats, arachidonic acid and DHA (docosahexaenoic
acid), make up the bulk of brain and central nervous system tissue. C.
Leigh Broadhurst, a nutrition scientist, and others have wondered where
early humans got these fats in the diet, since they are not abundant in
the ordinary savanna landscape. [33].
However, these fats are abundant in fish and shellfish. Humans evolved in an area, the
African Rift Valley, that was endowed with lakes and streams. Humans of
that time freely consumed shellfish, fish, wading birds, and ducks and
their eggs. Leigh Broadhurst calculates that the quantities consumed did
not have to be large—just 6% to 12% of calories [34].
Fatty
Acids in the Body
There are dozens of fatty
acids, most of which are either neutral or harmful to health. Saturated
myristic acid and palmitic acid are aggressive to arteries. They are
particularly found in butter, cream, cheese, beef, pork, and lamb.
Palmitic acid is also the chief component of palm oil, which is used in
processed foods.
However, the body converts another saturated fat, stearic acid
(particularly found in cocoa butter), into oleic acid (as found in olive
oil). Oleic acid, which dominates the family of monounsaturated fats, is
neutral on the body. Olive oil
Above Page 106
is “good” because it does no harm.
When it comes to consuming fats and oils, we have to realize that in
nature they come as a cocktail of many varieties. For example, the chief
components of pork fat are the saturated fats palmitic acid (24%),
stearic acid (13%), and myristic acid (2%); the monounsaturated fats
oleic acid (41%) and hexadecenoic acid (2%); and the polyunsaturated
omega-6 fat linoleic acid (4%). In other words, it is mainly composed of
fats that are innocuous—just the palmitic and the myristic acids,
totaling 26%, are harmful. However, that is enough for damage to be
done.
Fatty acids are present in our bloodstream bound up into a compound
called a triglyceride. A triglyceride is composed of a molecule of
glycerol to which three fatty acids are attached. When we eat a
triglyceride molecule, digestive enzymes split it apart into its
component fatty acids (plus the glycerol).
These components pass through the gut wall into the bloodstream, where
the body reconstructs the fatty acids into a different triglyceride.
Depending on the fatty acid’s position (1, 2, or 3) on the original
molecule, it is more or less “bioavailable” [35].
In human biochemistry, fats in position 2 are very
easily absorbed, while the others in positions 1 and 3 are not. Pork fat
finds 66% of its worst fatty acids in position 2, which is why pork fat
is so much more harmful than a simple analysis of its saturated fat
content would suggest. The same is true for butter and cream. On the
other hand, cocoa butter, which contains 60% saturated fat, finds 95% of
it parked harmlessly in positions 1 and 3 [36]. Harmless monounsaturated fats occupy 85% of position 2, from
where fatty acids are easily absorbed. That is why cocoa is far less
cholesterolemic than a simple examination of its saturated fat content
would suggest..
Calcium in the gut also combines readily with fatty acids to form
insoluble compounds that cannot be absorbed into the body. This is the
fate of much of the calcium in milk—it is locked up with the milk fats
and both are passed out in the stools. In cheeses, researcher Serge
Renaud has shown that this appears to be the mechanism where unhealthy
saturated fats are shown the back door [37]. This seems to be one part of the explanation for the French
Paradox: most of the “bad” cheese fats are not absorbed into the
body.
Humans in our ancient homeland did not find much fat in their diet, so
they never developed a mechanism for knowing when they had eaten enough.
Because some fats are essential, we have a well-developed mechanism to
keep eating them for as long as supplies last. However, our bodies do
not know how to discriminate between what is essential (and beneficial)
and what is nonessential (and often harmful), and we pay the price.
Fatty foods taste good and trigger the approval mechanism in the brain,
which gives us that feeling of comfort.
We’ve seen that humans are adapted to a low-fat diet, but what fat
there is should be of two particular kinds, omega-3 and omega-6.
Moreover, these two types of fat should be consumed in the ratio of
about 1 to 1. In recent years, our
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pattern of fat consumption
has changed dramatically, with the arrival of omega- 6 vegetable oils on
the market. Their dominance over omega-3 is responsible, at least in
part, for the rapid increase in a range of diseases.
Salt/Potassium Ratio
The Savanna Model diet is low in sodium and rich in potassium.
Sodium, of course, is the active component of salt. Potassium is an
element mainly found in plant foods, chiefly fruit. To expand on what we
said under “Salt” in chapter 3: The evolutionary nutritionist Boyd
Eaton estimates that the typical consumption in Pleistocene times was
about 1 grams of sodium to 5 grams of potassium [38]. Consequently, this ratio is important for the
proper functioning of our biochemistry, particularly at the cellular
level. Today, the average American has reversed this ratio and consumes
6 grams of sodium to 2.5 grams of potassium— and it matters!
Medical researcher Louis
Tobin shows that salt damages arteries even if blood pressure is not
raised [39]. High salt levels irritate and scar the arteries, making it one
more factor in the development of atherosclerosis.
High sodium levels also affect the way calcium is mobilized by the body.
Canadian researchers have shown that over-consumption of salt drains
calcium out of the bones [40]. Other studies confirm that potassium and sodium
imbalances destroy bone building [41]. This is just one more example
of how today’s dietary practices are greasing the slippery slope
toward osteoporosis.
As with fats, salt is a compound that our brains tell us to eat while
the going is good. That is because in our evolutionary past salt was
never abundant and it was impossible to overconsume it. It is only in
recent times that salt has passed from being a rare luxury to an
all-pervading flavor enhancer. In the quantities that we consume today,
salt is one of the many factors undermining our health. Salt is yet
another food where we have defeated nature’s discipline of natural
scarcity, so we should be exercising self-discipline to reinstate
scarcity in our diets.
Acid/Alkali Balance
Acids are compounds that
taste sour and eat away at metals. Examples are the citric acid in
lemons, acetic acid in vinegar, and sulfuric acid in car batteries.
Alkalis (also known as “bases”) are the opposite; in a way, they are
the antidote to acids. For example, the stomach contains hydrochloric
acid, which sometimes causes indigestion; the antidote is an alkali (or
“antacid”), such as sodium bicarbonate and magnesium hydroxide. When
acid and alkali cancel each other out, the result is neutrality—the
blood is neither acid nor alkaline.
All foods, once digested and absorbed into the bloodstream, will cause
the blood to be either more acidic or more alkaline. Clinical researcher
Anthony Sebastian confirms that nature designed human biochemistry to
work on a
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broadly neutral diet [42]. This is not like a cat, for example, which functions best on an
acid diet, nor like a horse, which prefers an alkaline diet. In humans,
the body is constantly juggling to restore a neutral balance.
What are alkali-forming foods? They are ones that have a predominance of
the metallic elements potassium, sodium, iron, and calcium—chiefly
fruit, salads, and non-starchy vegetables. This demands an explanation,
because many of these foods, notably fruit, taste acid but are, nevertheless, alkalizing in effect.
For example, grapefruit, although acid to the taste, is strongly
alkalizing. The answer to this paradox lies in what happens after the
digestive system has broken down the acid into its parts.
The acid taste of many fruits is due to the presence of organic acids,
such as citric acid and malic acid. This acid stays intact through the
mouth, the stomach, and into the intestine. Up to this point, the effect
on the digestive process and lining is acidic. But in the intestine, the
organic acid passes through the intestinal wall into the bloodstream.
Here, it is broken down into two parts: carbonic acid, which is blown
out of the body through the lungs in the form of carbon dioxide, and the
alkaline portion, which is left behind to alkalize the body.
What are acid-forming foods? Not foods that taste acid, but rather the
ones that after digestion and metabolism have the effect of acidifying
the body. They are foods that contain sulfur, phosphorus, and
chlorine—found chiefly in proteins like meat, fish, eggs, and cheese.
For example, bland roast chicken is one of the most acidifying foods
around. Starches like bread, flour, pasta, and cereals are also acid
forming.
The body compensates for an acid diet by drawing down reserves of
calcium, sodium, and potassium to neutralize the acid and excreting the
waste through the kidneys. The average person eating a Western diet has
chronically acidified his body, disrupting many biochemical mechanisms.
For example, an acid diet irritates the kidneys into abnormally leaking
calcium into the urine.
This phenomenon, known as protein-induced calciuria, is a major
mechanism for bone demineralization. Considering the epidemic proportion
of osteoporosis in this country, it is a vital fact that too few people
know. This knowledge also explains how, on a high-meat, highly acidic
diet, the Eskimo suffers from osteoporosis even though he has a high
calcium intake.
The Eskimo’s high-meat diet provides protein in excess of the body’s
requirements. The body cannot tolerate excess protein in the
bloodstream, so it immediately mobilizes the kidneys to get rid of it.
In turn, the kidneys have to extract more water from the bloodstream to
provide the necessary fluid for flushing the waste proteins out in the
urine. This has two consequences. This extra urination leads to
dehydration and abnormal feelings of thirst—the reason why Eskimos
were driven to downing vast quantities of water on their high-meat
diets. Second, nature did not design the kidneys to work like this on a
continuous basis.
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Waste protein cells and calcium-bearing cells crystallize into
hard nodules. These are the kidney stones that block kidney ducts and
cause immense pain.
Many other organs, including the pancreas, lymphatic system, thyroid,
intestines, and liver are either dependant on or responsible for a
neutral environment. They are put under abnormal stress and can fail if
they continually have to compensate for an unrelenting acid diet.
Nutrition researchers Robert McCance and Elsie Widdowson formed a
remarkable partnership for over 60 years. They established the
specifications for British wartime rations during World War II and the
British nation has never been healthier since that time, when the
portions of food were metered with tight discipline and only foods
essential to the human body were made available. McCance and Widdowson
worked out indexes of acidity and alkalinity for many foods [43].
Food
|
Index
|
Very
Alkaline
|
|
Almonds
|
18.3
|
Avocados
|
10.7
|
Grapefruit
|
6.4
|
Tomatoes
|
5.6
|
Cucumber
|
3.2
|
Apples
|
3.0
|
Neutral
|
0
|
Bread,
toasted
|
–2.6
|
Cheese,
cheddar
|
–5.4
|
Spaghetti
|
–7.5
|
Peanuts
|
–11.6
|
Bacon
|
–17.0
|
Chicken,
roasted
|
–25.4
|
Very
Acid
|
|
So, what pattern of eating does
this imply? Notice that the acid-forming foods (mainly proteins) are dense compared to the alkali-forming ones (mainly non-starchy plant
food). That is to say, the plant food is more watery than the proteins.
We also see how in today’s diet, starches, which are acidic, displace
other kinds of plant foods that are alkalizing.
On average, it takes three times as much plant food as protein to
maintain a neutral balance; in other words, about 75% by weight of plant
food to 25% of protein in the diet. This same ratio also provides the
right amount of protein in
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the diet, neither an excess
or a deficit. Have we seen this ratio before? It is not a coincidence
that both the San and the Australian Aboriginal consumed a very similar
ratio of plant food to animal food. This is another piece of evidence
confirming the natural adapted eating pattern for human beings—one in
which non-starchy plant food occupies about three-quarters of what we
eat and foods of animal origin about one-quarter.
Summary—Biochemical Clues
We have delved into how the food we eat is a major influence on
the human body’s biochemical processes. It is a complex subject and
our knowledge is far from complete. We cannot predict with certainty
that what we do today will have the same results tomorrow. This
reinforces our idea that, perhaps, we should not even be trying to
micromanage these processes. Instead, we should simply consume the foods
that our body expects and it will sort these matters out for itself.
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