Meat in the
Human beings have
been consuming meat as part of their diet for most of their existence and
will likely continue this behavior until the last living animal is gone
from the earth. However, public awareness of meat-associated health
hazards, such as heart attacks, colon cancer, and fatal E. coli bacterial
infections, has caused great concern and shifts in many people’s eating
habits. The number of vegetarians has been growing worldwide, especially
among better-educated and younger people. An astonishing contradiction to
this trend is today’s most popular weight loss diet – the Atkins Diet –
almost entirely meat. Obviously, there is still much disagreement and
There is no more
important question to be answered for mankind than, “What is the proper
diet for human beings?” What is the diet that allows us to look, feel,
and function at our best? Not just to survive or lose weight. Is it
vegetarian? Does it contain meat? How much meat? There must be a
correct answer. Just like there is one diet best for horses, one for
cats, one for dogs, and one for each kind of bird – there must be one diet
best for people.
Why have we not
discovered this diet? It is certainly not because of lack of interest.
Russell Henry Chittenden,
the father of American biochemistry and professor
of physiological chemistry at Yale Medical School, wrote, a century
ago (1904), “We hear on all sides widely divergent views regarding the
needs of the body, as to the extent and character of food requirements,
contradictory statements as to the relative merits of animal and vegetable
foods; indeed, there is a great lack of agreement regarding many of the
fundamental questions that constantly arise in any consideration of the
nutrition of the human body.” You would think that after so many years of
investigation using the latest scientific methods and employing modern
technology that this matter of such grave importance would have been
settled beyond a doubt. Coexistence today of enthusiastic advocates of
“all meat” and “no meat” diets, and everything in between, proves this
matter is far from settled.
Believe, the Less Meat, the Better
Over my past 25 years
of medical practice I have taken the position that meat at most should be
considered a delicacy, reserved for consumption on special occasions by
healthy people. The consequence of this belief is my patients lose excess
weight and become healthy – and stay this way for a long lifetime.
Regardless of how much others may argue the merits of their opinions on
the best diet (supported, of course, by all the latest “facts”), they do
not have the same glowing outcomes with their patients – I’ve seen the
consequences. For me, as a practicing doctor, the bottom line is
patient results. Fortunately, there is an overwhelming amount of
undeniable scientific data and observations clearly supporting my
conclusions. I will share this information with you.
Should We Follow
Our Ancestors’ Diets?
Many scientists use
the diet of our ancestors as the justification for what we should eat
today. That may be a useful approach, but which ancestors are we to
follow? Differences of opinion arise because throughout human history
people have consumed a wide variety of foods. The
early ancestors of modern humans, from at least 4 million years ago,
followed diets almost exclusively of plant-foods. Beginning at least 250,000 years ago, many of the
hunter-gatherer societies consumed meat as a large part of their diet.1
However, more recently, over the past 12,000 years of agricultural
development, people’s diets have been mostly based upon starches, like
rice in Asia, corn in North America, potatoes in western parts of South
America, wheat in Europe and Northern Africa. In terms of the time line
of evolution, 12,000 years, and even 250,000 years, is only a brief
Out of the
Garden of Eden
The Bible story of
Adam and Eve’s eviction from the Garden of Eden is closely analogous to
the actual shift from early plant-eating humans to hunter-gatherers.2
While in the Garden God said, “I give you every seed-bearing plant on the
face of the whole earth and every tree that has fruit with seed in it.
They will be yours for food.” Upon expulsion humans were instructed by
God, “By the sweat of your brow you will eat your food.”
For the most part
hunter-gatherers (i.e., exiles from the Garden) had a subsistence standard
of living, eating foods
that extended from one extreme to the other in proportions of plant vs.
animal foods – from the raw flesh and fat of marine mammals – the Arctic
Eskimos – to diets composed largely of wild plants of the Western Desert –
Australian Aborigines.3 Hunter-gatherers took advantage of any
dependable sources of food from their wild local environments. Because of
the ease and dependability (compared to obtaining animals), gathering
fruits and vegetables was a primary source of food for most
hunter-gatherer societies – the emphasis on hunting increased in higher
latitudes because of plant scarcity.4
Undoubtedly, all of
these diets were adequate to support growth and life to an age of
successful reproduction. To bear and raise offspring you only need to
live for 20 to 30 years, and fortuitously, the average life expectancy for
these people was just that. The few populations of hunter-gatherers
surviving into the 21st Century
are confined to the
most remote regions of our planet – like the Arctic and the jungles of
South America and Africa – some of the most challenging places to manage
to survive. Their life expectancy is also limited to 25 to 30 years and
infant mortality is 40% to 50%.5 Hunter-gatherer societies
fortunately did survive, but considering their arduous struggle and short
lifespan, I would not rank them among successful societies.
So why has meat
been an important part of the diet of so many of these hunter-gatherer
societies?6 Throughout human history, especially before the
development of agriculture-based living, acquiring food for survival was a
full time job – food scarcity, even starvation, plagued most of these
people, at least some of the time. Meat represented a gold mine of
concentrated calories and nutrients whenever it was obtained. For those
societies who found a plentiful supply, survival on a meat-based diet
simply attests to the resilience and adaptability of the human frame.
hunter-gatherer societies obtained most of their calories from the fat of
meat does not mean meat is the ideal diet for modern people. Almost every
scientist readily admits that the composition of wild game available to
our ancestors was far different from the grain-fed domesticated high-fat
meat people eat these days. Furthermore, even if humans have been eating
meat for centuries, it has not been with the ease that wealthy Westerners
acquire it today. Without refrigeration and other means of preserving
meat in a near fresh state, consumption was limited to within a few days
of the kill – until the meat spoiled. (With the advent of fire people
learned to preserve meat by smoking it.)
times meat provided more benefits than harms, but in a society where food
is plentiful and life is physically easy, meat can become a serious health
hazard. A traditional Arctic Eskimo, living in a subfreezing climate,
could expend 6000 calories and more a day just to keep warm and hunt for
food. The high-fat animal food sources – fish, walrus, whale, and seal –
from his local environment were the most practical means of meeting the
demands of those rigorous surroundings. Modern Eskimos living in heated
houses and driving around in their climate-controlled SUVs, still
consuming a high-meat diet, have become some of the fattest and sickest
people on earth. Of course, they now use a “green lure” (a $10 bill) to
catch their fish (sandwich).
Our Anatomy and
Physiology Provide the Undeniable Evidence3,4,8,9-13
Evolution in the
animal kingdom dates back hundreds of millions of years and the evolution
of humans began over 4 million years ago. The
ancestors of modern humans were believed to live primarily on plant foods,
eating wild fruits, leaves, roots, and other high quality plant parts with
a few animal foods in their daily diet. These pre-humans ate like our
nearest primate relatives, the apes of today.3 Now,
biologists at Wayne State University School of Medicine in Detroit,
Michigan, provide new genetic evidence that lineages of chimpanzees and
humans diverged so recently that chimps should be reclassified as members
of our genus Homo, along with Neanderthals, and all other
human-like fossil species.7 “We humans appear as only slightly
remodeled chimpanzee-like apes,” says the study.
Most apes living
today eat essentially as vegetarians – consuming a diet composed of the
fruits, leaves, flowers, and bark, with sporadic consumption of very small
amounts of insect material (like termites) and less commonly, small
animals.8 These meat-eating activities may be purely social in
nature and unrelated to any real nutritional needs.
Behavior can be
changed overnight, but our anatomy and physiology only evolve from
selective pressures of the environment over millions of years. Food is
the strongest contact with our environment. Therefore, the present state
of the human body accurately reflects how our kind has eaten during most
of our human and pre-human existence. These indisputable anatomical and
physiological characteristics clearly identify the best diet for people
Have the Mouth of a Plant-Eater
“Johnny, eat your
beef, you have to get your protein.” Worried about her growing child, my
mother said this to me at almost every dinnertime. “But Mother, I can’t
chew it,” I tried to explain. To make her happy I mashed the bite-size
piece of roast beef with my teeth into a leathery lump, still too big to
comfortably swallow. Eventually, jaw tired, wanting to be excused from
the table, I slipped the remains under the edge of my plate. All this
distress could have easily been avoided if my mother had known enough
truth about good nutrition to simply say “Of course you can’t chew that
meat – you have the wrong kind of teeth, Johnny – give it to the dog.”
evolved for processing starches, fruits, and vegetables, not tearing and
masticating flesh. Our oft-cited "canine" teeth are not at all comparable
to the sharp teeth of true carnivores. I lecture to over 10,000 dentists,
dental hygienists, and oral specialists every year, and I always ask them
to show me the “canine” teeth in a person’s mouth – those that resemble a
cat’s or dog’s teeth – I am still waiting to be shown the first example of
a sharply pointed canine tooth.
If you have any
doubt of the truth of this observation then go look in the mirror right
now – you may have learned to call your 4 corner front teeth, “canine
teeth” – but in no way do they resemble the sharp, jagged, blades of a
true carnivore – your corner teeth are short, blunted, and flat on top (or
slightly rounded at most). Nor do they ever function in the manner of
true canine teeth. Have you ever observed someone purposely favoring
these teeth while tearing off a piece of steak or chewing it? Nor have
I. The lower jaw of a meat-eating animal has very little side-to-side
motion – it is fixed to open and close, which adds strength and stability
to its powerful bite. Like other plant-eating animals our jaw can move
forwards and backwards, and side-to-side, as well as open and close, for
biting off pieces of plant matter, and then grinding them into smaller
pieces with our flat molars.
In a failed attempt
to chew and swallow pieces of food, usually meat, approximately 4,000
people die each year in the U.S.14 They choke on inadequately
masticated chunks that become stuck in their throats. The Heimlich
maneuver was specifically designed to save the lives of people dying from
these “café coronaries.”14.
Digestive System Assimilates Plant Foods4,8
From our lips to
our anus our digestive system has evolved to efficiently process plant
foods. Digestion begins in the mouth with a salivary enzyme, called
alpha-amylase (ptyalin), whose sole purpose is to help digest complex
carbohydrates found in plant foods into simple sugars. There are no
carbohydrates in meats of any kind (except for a smidgen of glycogen), so
a true carnivore has no need for this enzyme – their salivary glands do
not synthesize alpha amylase.
The stomach juices
of a meat-eating animal are very concentrated in acid. The purpose of
this acid is to efficiently break down the muscle and bone materials
swallowed in large quantities into the stomachs of meat-eaters. Digestion
of starches, vegetables and fruits is accomplished efficiently with the
much lower concentrations of stomach acid found in the stomachs of people,
and other plant-eaters.
The human intestine
is long and coiled, much like that of apes, cows, and horses. This
configuration makes digestion slow, allowing time to break down and absorb
the nutrients from plant food sources. The intestine of a carnivore, like
a cat, is short, straight, and tubular. This allows for very rapid
digestion of flesh and excretion of the remnants quickly before they
putrefy (rot). There are also marked sacculations (many sac-like
enlargements that bulge out along our large intestine), like those found
in all apes, which strongly supports the view that we are primarily
plant-eating animals. Overall, the intestines of meat-eaters are
noticeably simpler than ours.
Overwhelms a Plant-eater’s Liver15
Cholesterol is only
found in animal foods – no plant contains cholesterol. The liver and
biliary system of a meat-eating animal has an unlimited capacity to
process and excrete cholesterol from its body – it goes out, in the bile,
passing through the bile ducts and gallbladder, into the intestine, and
finally, out with the stool. For example, you can feed a dog or cat pure
egg yolks all day long and they will easily get rid of all of it and never
suffer from a backup of cholesterol. Humans, like other plant-eating
animals, have livers with very limited capacities for cholesterol removal
– they can remove only a little more than they make for themselves for
their own bodies – and as a result, most people have great difficulty
eliminating the extra cholesterol they take in from eating animal
products. This apparent “inefficiency” is because humans have evolved on
a diet of mostly plant foods (containing no cholesterol), and therefore,
they never required a highly efficient cholesterol-eliminating biliary
system. The resulting cholesterol buildup, when people eat meat, causes
deposits in the arteries (atherosclerosis), in the skin under the eyes
(xanthelasma), and in the tendons. Bile supersaturated with cholesterol
forms gallstones (over 90% of gallstones are made of cholesterol). About
half of all middle-aged women who live on the Western diet have
cholesterol gallstones. (See my April and May 2002 Newsletters.)
Requirements are for Plant Nutrients4,8
To believe we
require the body parts of other animals in our diet for good health
supposes the human body evolved over many millions of years on a diet
predominantly of meat – and deficient in plants. This is not what is seen
when the nutritional requirements of people are examined.
When plants have
been for eons a plentiful and reliable part of the diet, an animal can
become dependent upon specific nutrients found in these foods. For
example, ascorbic acid – found preformed and ready to use in plant foods –
is called vitamin C in the diet of people. Insufficient amounts of this
vitamin cause scurvy. Vitamins are essential micronutrients that cannot be
synthesized by the body; and therefore, must be in the food. Because
ascorbic acid has not been reliably available to them, meat-eating animals
have retained the ability to synthesize ascorbic acid from basic raw
materials found in their meat diet – therefore, it is not a vitamin for
them. (In other words it is not “vital” or essential to be preformed in
their food supply.)
Because humans have
lived throughout most of their evolution on diets with very little animal
matter, they have had to develop or retain the ability to synthesize some
substances they need that are abundantly found in meat. For example,
humans, and other plant-eating animals, have the ability to make vitamin A
from a precursor found in large quantities in plants, called
beta-carotene. Carnivores cannot utilize beta-carotene as a precursor of
vitamin A. They have no need to; throughout their evolution they have
always had a plentiful supply of preformed vitamin A (Retinol) found in
the meat. Carnivores have also lost the ability to synthesize Niacin,
which is plentiful in meat. Remember, efficiency is necessary for survival
of a species and it is inefficient to keep manufacturing processes in the
body that are useless.
Instincts Are for Plants
enlightened people in modern Western nations, the idea of chasing down and
killing an animal is revolting; and the thought of consuming that freshly
killed flesh is repulsive. (And to eat decaying flesh, as a vulture does,
would be next to impossible.) Even when meat is cooked, most people are
disgusted by the thought of eating a slice of horse, kangaroo, rat, or
cat. Cows, chickens and pigs are acceptable to most Westerners only
because we have eaten them all of our lives. Yet even then, to make meat
palatable, its true nature must be covered up with a strong flavored sauce
made with salt, sugar, and/or spices – like sweet and sour, marinara,
barbecue, or steak sauce. Few people enjoy boiled beef or chicken.
People do not have
a negative reaction to unfamiliar fruits and vegetables. Consider, I
could ask you to try an unfamiliar “star fruit” from the tropics for the
first time and you would eat and enjoy it without hesitation. Why?
Because your natural instincts are to eat fruits and vegetables.
Should Eat Like You Act
So many human
characteristics clearly say we evolved to be primarily plant-eaters. Do
you want to read more? Our hands are made for gathering plants, not
ripping flesh. We cool ourselves by sweating, like most other plant-eating
animals. Carnivores cool their bodies by panting. We drink our beverages
by sipping, not lapping like a dog or cat. The exhaustive factual
comparisons of our body traits with that of other animals prove we have
evolved over eons in an environment of plant-based foods – the only real
contradiction is our behavior. The results of our aberrant behavior can
be catastrophic – let me begin to explain that harm with one example about
A Man’s Behavior
Contradicts His Anatomy
traditionally have been the hunters who carry back the slain animals to
feed the village – you know, “they bring home the bacon.” Scientific
research confirms meat is viewed as a superior masculine food.16
The acts of killing, butchering and eating animals are associated
with power, aggression, virility, strength, and passion – attributes
desired by most men – and eating meat has long been associated with
aggressive behaviors and violent personalities. Men say they need more,
and they do eat more meat, especially more red meat, than women. However,
based on male anatomy, real men should be vegetarians.
Human males have
seminal vesicles – no other meat-eating animal has these important
collecting-pouches as part of their reproductive anatomy.17 The
seminal vesicles are paired sacculated pouches connected to the prostate,
located at the base of the bladder. They collect fluids made by the
prostate that nourish and transport the sperm. Ejaculation occurs when
the seminal vesicles and prostate empty into the urethra of the penis. In
many ways ejaculation is the ultimate act of male performance – seminal
vesicles are essential organs for proper male function and therefore, they
should tell us much about his true nature.
Behavior Ruins His Potency
diminishes sexual performance and masculinity. The male hormone
testosterone that determines sexual development and interest has been
found to be 13 % higher in vegans (a strict plant diet – no animal
products of any kind) than in meat-eaters.18 Meat-eaters are
likely to become impotent because of damage caused to the artery system
that supplies their penis with the blood that causes an erection.19
Erectile dysfunction is more often seen in men with elevated cholesterol
levels20 and high levels of LDL “bad” cholesterol21–
both conditions related to habitual meat-eating.
The greatest threat
to a man’s virility is from the high levels of environmental chemicals
concentrated in modern meats of all kinds. These chemicals interfere with
the actions of testosterone. Decreased ejaculate volume, low sperm count,
shortened sperm life, poor sperm motility, genetic damage, and infertility
result from eating meat with estrogen-like environmental chemicals.22
These chemicals in the meat, eaten by his mother, influence the
development of the male fetus, increasing the risk that the baby boy will
be born with a smaller penis and testicles, as well as deformity of the
penis (hypospadia) and an undescended testicle (cryptorchism). Estimates
are 89% to 99% of the chemical intake into our body is from our food, and
most of this is from foods high on the food chain – meat, poultry, fish,
and dairy products.23,24
A Deviant Diet
Causes Deadly Diseases
diet for humans today is centered around starchy plant foods with the
addition of fruits and vegetables – the use of clean meat is limited to
special occasions – like Thanksgiving and Christmas – and consumed only by
healthy people.25 If your diet deviates too far from that
which you evolved on over eons of time then you will likely suffer serious
consequences – these are the chronic diseases affecting people living on
the Western diet. Next month I will continue this discussion of the
health problems produced when we attempt to live with meat as a
significant part of our diet.
1) Wood B. Human
evolution: We are what we ate.
Nature 1999;400:219 - 220
2) Bible (New
International Version): Genesis 1:29 and 3:19
3) Milton K. Back to
basics: why foods of wild primates have relevance for modern human health.
Nutrition. 2000 Jul-Aug;16(7-8):480-3.
4) Milton K.
Hunter-gatherer diets-a different perspective. Am J Clin Nutr.
5) Nestle M. Animal
v. plant foods in human diets and health: is the historical record
unequivocal? Proc Nutr Soc. 1999 May;58(2):211-8.
6) Cordain I. The
paradoxical nature of hunter-gatherer diets: meat-based, yet
non-atherogenic. Eur J Clin Nutr. 2002 Mar;56 Suppl 1:S42-52.
7) Chimpanzees are
also in the Homo species:
8) Milton K. A
hypothesis to explain the role of meat-eating in human evolution. Evol
9) W. Collens,
“Phylogenetic Aspects of the Cause of Human Atherosclerotic Disease,”
Circulation (suppl II) 31-32 (1965): II-7.
10) C. Prosser,
Comparative Animal Physiology , 2nd ed. Philadelphia: W. B.
Saunders, 1961, p. 116
11) E. Nasset,
Movements of the small intestine, P. Bard, Medical Physiology, 11 ed. C.
V. Mosby, 1961, St. Louis, p. 440
12) Carpenter KJ. Protein requirements of adults from an
evolutionary perspective. Am J Clin Nutr. 1992 May;55(5):913-7
13) Mills M. The
Comparative Anatomy of Eating
14) H. Heimlich, “A
Life-Saving Maneuver to Prevent Food-Choking,” JAMA 234 (1975):
15) Dietschy J.
Regulation of cholesterol metabolism. 3. N Engl J Med. 1970 May
16) Roos G.
Men, masculinity and food: interviews with Finnish carpenters
and engineers. Appetite. 2001 Aug;37(1):47-56.
Coffey D. Similarities of prostate and breast cancer:
Evolution, diet, and estrogens.
Urology 57(4 Suppl 1):31-8, 2001.
18) Allen NE.
Hormones and diet: low insulin-like growth factor-I but
normal bioavailable androgens in vegan men. Br J Cancer. 2000
19) Feldman HA.
Erectile dysfunction and coronary risk factors: prospective
results from the
male aging study. Prev Med. 2000 Apr;30(4):328-38.
20) Bodie J.
Laboratory evaluations of erectile dysfunction: an evidence
based approach. J Urol. 2003 Jun;169(6):2262-4.
21) Walczak MK
Prevalence of cardiovascular risk factors in erectile
J Gend Specif Med. 2002 Nov-Dec;5(6):19-24.
22) Rozati R
. Role of environmental estrogens in the deterioration of male factor
fertility. Fertil Steril. 2002 Dec;78(6):1187-94.
Polychlorinated biphenyls (PCBs) in the
UK population: estimated
intake, exposure and body burden. Sci Total Environ. 1994 Jul
24) Liem AK.
Exposure of populations to dioxins and related compounds.
Food Addit Contam. 2000 Apr;17(4):241-59.
25) Segasothy M.
Vegetarian diet: panacea for modern lifestyle? Q J Med 92:531-544,