Eat Right for Your Type?
An extract from The Food
Revolution, a book by John Robbins
http://www.positivehealth.com/Reviews/books/robbins67.htm
The book Eat Right for Your Type by Peter J. D�Adamo
proposes that there are four different ideal diets, one for each blood
type: A, B, AB, and O. Follow the diet that is �right for your type�, he
says, and you can lose weight, cure ear infections, fight off cancer, heal
yourself from Chronic Fatigue Syndrome, and much, much more. By �eating
right for your type,� D�Adamo asserts, you will be eating like your
prehistoric ancestors did.70
This may sound very appealing. In a time when we have
strayed so far from a natural way of eating, a guide to eating like your
prehistoric ancestors could be quite helpful. And, indeed, many have been
drawn in by D�Adamo�s promises.
But according to the Tufts University Health and
Nutrition Letter, D�Adamo has his blood typing all wrong. �It�s a fallacy
even to speak of �original� type Os or �original� type As because blood
types did not originate with humans,� explains Dr Stephan Bailey, a
nutritional anthropologist at Tufts University. �They came on the biologic
scene long before humans did. Furthermore, there is no anthropologic
evidence whatsoever that all prehistoric people with a particular blood
type ate the same diet.�71
D�Adamo has come up with 16 different food groups,
further divided into �Highly beneficial,� �Neutral,� and �Avoid� foods,
depending entirely on what blood type you are. Type As, for example, are
told they do well on vegetarian diets, but they should avoid cabbage,
potatoes, eggplant, olives, peppers, and tomatoes, among many other foods.
They are, however, advised to eat snails.72
Type Os, on the other hand, are told to base their diets
heavily around red meat. They are told to avoid oranges, apples, wheat,
peanut butter, avocados, cabbage, and potatoes, but encouraged to eat
veal, ground beef, and beef heart.
D�Adamo tells Type Bs to eat a lot of dairy products,
including frozen yoghurt. He tells them to avoid sunflower seeds, garbanzo
beans, pinto beans, whole wheat bread, corn, pumpkin, tofu, tempeh, and
tomatoes, but encourages them to eat rabbit, lamb, and mutton.
Type ABs are told to avoid corn, peppers, olives,
sunflower seeds, sesame seeds, and lima beans, but encouraged to eat jam,
jellies, rabbit, and turkey.
Many people who have tried D�Adamo�s diet have lost
weight. There is a reason, but it isn�t the one he gives. In actuality,
the diets recommended for all four blood types are each extremely low in
calories. Some day�s plans have only 1,000 calories, half the caloric
needs of an adult woman.
Nevertheless, for D�Adamo, virtually everything in life
comes down to whether you are an A, B, AB, or O blood type. According to
him, �(ABO) blood type can determine so many things: how much and how
often we should eat; what our optimal daily schedule should be; what our
best sleep/rest patterns are; how stress affects us and how to combat it;
how to maximize our health; how to overcome disease; how we deal with
aging; and even our degree of emotional well-being.�73
D�Adamo believes that people who are type O and type B
must eat meat daily to be healthy. When confronted with the fact that
vegetarian diets have been consistently shown to produce lower rates of
cancer, heart disease, hypertension, diabetes, gallstones, kidney disease,
obesity, and colon disease, and to enable people to live longer and more
healthfully, he explains that type As do well on vegetarian diets. It is,
however, mathematically impossible that the health advantages for
vegetarians could be accounted for only by type As benefiting from the
absence of meat. According to the Red Cross blood bank, the population of
the United States is approximately 39 percent type A, 46 percent type O,
11 percent type B, and 4 percent type AB.74 There is no possible way that
the consistent superiority of vegetarian diets that has been demonstrated
repeatedly by world medical research could be due to vegetarian diets
having health advantages only for type As, who are, after all, a minority
of the population.
Similarly, D�Adamo�s explanation for the success of Dr
Dean Ornish�s program of reversing heart disease, which includes putting
people on a near-vegan diet with no meat, is that it has only worked for
type As. It does not, he says, help type Os, type Bs, or type ABs.75
I asked Lee Lipsenthal, MD, the vice president and
medical director of Dr Dean Ornish�s Preventive Medicine Research
Institute, whether this might be possible. He replied,�There is no
evidence in the scientific literature associating blood typology with
nutrient needs. Although heart disease almost invariably gets worse, even
when patients follow the American Heart Association recommendations, most
of our patients have shown actual reversal of their disease, and the vast
majority have shown measurable improvement in many areas � improved
physical function on exercise tests, improved blood flow to the heart
muscle, improved mood and sense of vitality, improved cholesterol levels,
improved blood pressure, improved sleep patterns, and improved social
function. We�ve had many hundreds of patients show dramatic improvements,
and all this has been measured by objective tests. I don�t see any
possibility that people with blood types 0 and B (who together represent
nearly 60 percent of the population of the U.S.) are not being helped by
the Ornish program.�76
D�Adamo believes that the risk of heart disease for type
Os is reduced by eating meat.77 There is, however, no evidence in the
world medical literature for this belief. The blood-type diet�s
explanation for why type Os presumably need meat is that type Os do �well
on animal products and protein diets � foods that require more stomach
acids for proper digestion.� In fact, D�Adamo says that �type Os can
efficiently digest meats because they tend to have high stomach acid
content.�78
It is well known, however, that not all men and women
with type O blood produce more hydrochloric (stomach) acid; some secrete
normal levels and some have less than normal. Further, it is pepsin, not
hydrochloric (stomach) acid, that is responsible for meat protein
digestion. In people who have large amounts of hydrochloric acid, the
stomach environment becomes unusually acidic. An especially acidic stomach
actually make pepsin less effective at digesting protein.79
D�Adamo�s beliefs regarding the diets of early humans,
likewise, seem to have no basis in fact. He writes, �The appearance of our
Cro-Magnon ancestors in around 40,000 BC propelled the human species to
the top of the food chain, making them the most dangerous predators on
earth� (with) little to fear from any of their animal rivals� (and no)
natural predators other than themselves. Protein � meat � was their fuel�
By 20,000 BC Cro-Magnons had... decimated the vast herds of large game.�80
The foundation of D�Adamo�s blood-type theory is his
belief that Cro-Magnons, who lived 40,000-20,000 years ago, were all type
Os and ate mainly meat. Types A, B, and AB came along later, he says, and
only they are genetically equipped for a diet that includes grains. There
is no evidence anywhere in the scientific literature, however, that
suggests Cro-Magnons were mainly or all type Os. Instead, there is
considerable evidence that all four blood types existed in the time of the
Cro-Magnons.
Were Cro-Magnons the heavy meat eaters D�Adamo portrays?
Not according to paleontologist Richard Leakey, who is widely acknowledged
as one of the world�s foremost experts on the evolution of the human diet.
Leakey points out, �You can�t tear flesh by hand, you can�t tear hide by
hand. Our anterior teeth are not suited for tearing flesh or hide. We
don�t (and Cro-Magnons didn�t) have large canine teeth, and we wouldn�t
have been able to deal with food sources that required those large
canines.�81
In fact, says Leakey, even if Cro-Magnons had large
canine teeth, they still almost certainly would only rarely have eaten
meat. Their diet would have been similar to that of the chimpanzee, our
closest genetic relative.
Molecular biologists and geneticists, Leakey says, have
compared proteins, DNA, and the whole spectrum of biological features and
have established very convincingly that humans are closer to chimpanzees
than horses are to donkeys. This is remarkable, because horses and donkeys
can mate and reproduce, although their offspring, mules, are sterile. A
significant difference between humans and chimpanzees, though, is that
chimpanzees have large canine teeth that can tear apart their prey, and
have more strength and speed than humans. Still, even with these traits,
which would be advantages for a meat-eater, chimpanzees, like other
primates, eat a mainly vegetarian diet. Dr Jane Goodall, whose work with
chimpanzees represents the longest continuous field study of any living
creature in science history, says chimpanzees often go months without
eating any meat whatsoever. Indeed, she says, �The total amount of meat
consumed by a chimpanzee during a given year will represent only a very
small percentage of the overall diet.�82
D�Adamo�s entire theory is based on his assumptions
about the blood types and diets of our prehistoric ancestors. Even though
his assumptions are wholly mistaken, however, his diet has been embraced
by many in the naturopathic community, and some schools of naturopathic
medicine have even begun to include this theory in their curriculum. As a
result, some naturopaths are now recommending that vegetarians and vegans
who are blood type O or B eat meat daily. However, other naturopaths
decisively disagree. The founder of naturopathy, Dr Benedict Lust, called
for �the elimination of� habits such as� meat eating.� Similarly, Henry
Lindlahr, MD, whose work has been widely read in naturopathic colleges,
defined naturopathy as favoring a �strict vegetarian diet.� After a
detailed and thorough discussion of the blood-type diet�s underpinnings,
contemporary naturopaths Dr Deirdre B Williams and Dr John J McMahon
conclude, �The blood type theory of diet doesn�t have a leg to stand
on.�83
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