'If I have not paid greater attention to my numerous critics, it is not that I have failed to study them; it is simply that I have remained --obstinately it may be-- convinced that the views expressed are, relatively to our present state of knowledge, substantially correct.' ---Karl Pearson, The Grammar of Science
Because of its potential effects on the scientific and economic status quo (especially the economic status-quo of other diet book authors), criticism of a theory like the blood type diets is unavoidable. You may have encountered the following criticisms of my work on the web. Rather than pretend that this type of misinformation will simply 'just go away', I've documented and reviewed some of these articles. I also provide links to the original material, so you can decide for yourself the benefits of this sort of dialogue.
Did a recent scientific study disprove the Blood Type Diet?
Yes, if you believe that a study of young, healthy research subjects eating potato chips, sandwiches, pizza, 'beans,' mac-and-cheese, French Fries and processed meat products, all the while doing 13.7% of the Blood Type Diet represented a fair test of the diets.
The responses are in most part rhetorical since none these criticisms present any proof for their assertions besides various opinions. Most are ad hoc offerings from acolytes of other dietary systems, fellow diet book authors and individuals who are fiercely opposed to naturopathic medicine. A special few are outright intellectually dishonest. Ask yourself, are you reading in the measured words of a true skeptic, or just the hand-waving of a denialist with an agenda?
Does the title include the word debunked? Using the term 'debunked' marks the source as a denialist with skin in the game. A true scientific, neutral point of view would mandate the use of less charged wording, such as this study fails to find support.
Keys to evaluating material critical to the Blood Type Theory (or any other scientific hypothesis)
Is it science-based, or just the postulations of a spokesman for
an opposing system threatened by its conclusions? Is the author opposed
to all forms of naturopathic medicine or alternative medicine? Will the author benefit in some way from defending the status quo?
Does the critic display a convincing knowledge of the human ABO
groups? We've found that many critics of Dr. D'Adamo's work have never
actually read any of his books, nor have they taken the time to
investigate the science. Is the author of the criticism an expert in the area? Many internet critics suffer from what psychologists call the 'Dunning-Kruger Effect', a type of cognitive bias in which fact-deprived people believe that they are smarter and more capable than they really are. This often leads criticisms based on the logical fallacy known as 'argument from incredulity' or 'argument from ignorance.'
Did the critic address their concerns directly with Dr. D'Adamo
writing their review? It is considered good journalistic practice to
present concerns directly to the authors of a study or book before
completing a review. This prevents misconceptions, encourages dialogue,
and allows for a more balanced editorial presentation. A clear
sign of a preconceived, slam-dunk ('Gotcha') review is that no effort is
made to afford the other side a chance to state their case. Two of the fundamental attributes of good journalism are curiosity and a continued open-mindedness about the people on whom you report.
Dr. El-Sohemy is a nutrigenomics researcher and an associate professor at the University of Toronto. He is a principal in Nutrigenomix, a company that markets genetic testing kits and dietary guideline to dieticians.
"Adherence to certain 'Blood-Type' diets is associated with favorable effects on some cardiometabolic risk factors, but these associations were independent of an individual's ABO genotype, so the findings do not support the 'Blood-Type' diet hypothesis."
A look at the core data used in the PLOS Study  debunking the Blood Type Diet (BTD) finds support for the researcher's conclusions that if your experimental subjects eat potato chips, sandwiches, pizza, 'beans,' mac-and-cheese, French Fries and processed meat products while doing 13.7% of the Blood Type Diet, their final cardiometabolic markers will probably not vary much by blood type. In other words, whilst the PLOS Study may have debunked something, it wasn't the Blood Type Diet. I've responded to this study on my blog:
Dr. Weil is a medical doctor. He has written
numerous books on alternative medicine. He has not authored any
peer-reviewed scientific papers on blood groups, nutrition or lectins.
He has not conducted any clinical research on blood groups and diet.
Diet Wars (Diet Book Author)
"D'Adamo theorizes that the basis for such differences is our
reactions to certain food proteins called lectins. Lectins are common
in plant foods, especially grains and beans, and may be involved in
food allergies and some immune disorders. But there is no convincing
evidence for any interactions between lectins and the molecules that
determine blood type."
"Yet some people swear the blood type diet has worked for them. There's a reason for that. Making changes in how we eat is not easy. To follow any prescribed dietary program with rules and restrictions represents a significant commitment of mental energy toward self-improvement. That alone can lead to a greater sense of well-being and better health. But if you want to eat a better diet, I recommend you rely on information grounded in nutritional science."
Dr. Weil is a well-known holistic doctor and author of numerous books
on diet. In a short article on the AARP online magazine, Dr. Weil again
argues that the Blood Type Diet should 'be sacked.' His opinion piece is shot-full of logical fallacies, including the fallacy of one-sidedness and the argument from incredulity (sometimes called "argument from ignorance").
Jettisoning his previous criticisms,
including the rather odd observation that animals have blood types and yet don’t follow the
Blood Type Diet, Dr. Weil now offers his opinions on the
lack of association between lectins and blood types. Dr. Weil's claim that there are no proven relationships between lectins and the molecules that determine blood type was apparently taken from an incorrect assertion that often finds its way onto the Wikipedia entry on the Blood Type Diet. This is hardly a hard-science resource.
In fact, blood group specificity is listed as one of the nine major factors influencing glycosylation in the gut (glycosylation is the process of manufacturing the sugar molecules that lectins bind with). Other factors include diet, age, animal species, disease and bacterial population. (Trends in Glycoscience and Glycotechnology; 8:149-165)
Dr. Weil is apparently still ignorant of the secretory differences (digestive enzymes, etc.) between the blood groups, perhaps the most significant reason behind the need for the tailoring nutritional needs to these genetic markers.
Dr. Weil may wish to consult the work of William Boyd, who first wrote of the blood type specificity of lectins more than a half century ago or reviewed the research of Martin Nachbar from the 1980's
before making such claims, since he is essentially just plain
trip to MEDLINE might have might have also proved helpful.,
William Boyd's 1945 work book has been preserved clearly showing blood type specificity of lectins he researched.
Did not contact Dr. D'Adamo prior to article
Searching MEDLINE for terms "ABO", "Blood", "Groups" and
687 published studies
A search on MEDLINE shows that Dr. Weil has not published any peer-review articles on nutrition and genetics.
McMahon, John J. ND (Wilton CT,
Williams, Deirdre B. ND (Wilton CT, USA)
throughout the internet, principally on vegan websites
Both authors are naturopathic
physicians. Neither have authored any peer-reviewed scientific papers
on blood groups, nutrition or lectins. Dr. McMahon has an undergraduate
degree in anthropology.
Opposing diet theory (veganism)
naturopathic physicians. We are also vegan
as are our children. The practice of naturopathy as originally
by Dr. Benedict Lust includes 'the elimination of... habits such as
over-eating, alcoholic drinks and... meat eating'. When we attended
the John Bastyr College of Naturopathic Medicine the work of Henry
Lindlahr, M.D. was required reading. Dr. Lindlahr defined the
of Nature Cure or naturopathy as favoring a 'strict vegetarian
diet' because of the 'morbid nature' of the 'alkaloids of putrefaction'
which 'every piece of animal
flesh is saturated with."
N.D. has recently published a
popular book in which he encourages a diet based on his interpretation
of the ABO blood groups and health. This blood type diet theory
encourages daily consumption of animal flesh by people of blood type O
and blood type B. Together these two blood types make up between 56%
69% of population of the United States. Schools of naturopathic
have begun to include this theory in their curriculum and our
often recommend a diet including daily consumption of animal flesh to
vegan/vegetarian patients of blood type O or B."
The foods we
eat contain lectins. Because of how
lectins clump (or "agglutinate") other molecules they have the
capacity to create health problems for human beings. Botulism toxin has
a lectin, ricin, that is so deadly you would never encourage someone to
there is evidence that enzymes such as intestinal transglutaminase,
secreted in response to certain lectins, repair lectin-induced
damages to the microvilli and gut epithelium In so doing
these enzymes would inhibit and occasionally eliminate
the potential for the chronic intestinal inflammation, bacterial
overgrowth and illness ascribed to eating "wrong" for your
Lindlahr and Benedict
Lust died in their early 60's. A recent study of 1200 people who
reached the century mark between 1932 and 1952 showed only four were
vegetarians. At some point in time, naturopathic medicine, and in some
peoples' minds health itself, became strongly associated with a
vegetarian diet. Some individuals within my own profession
that I had abandoned the core of naturopathic medicine by advocating
good quality meat for individuals of certain blood types.
Getting stuck in a belief system can be
place to dwell. Often a good question to ask is, "what does the
evidence show?" Naturopathic medicine developed from the
water cure movement of Europe. Theodor Hahn is credited as being the
first of the pioneers of this water cure movement to integrate
vegetarian dietetic principles. He was convinced that a meat-free diet
would prolong life. In fact he was so convinced of the value of a
vegetarian diet that he spent a great deal of his professional life
writing books and pamphlets on the subject and was the editor of a
magazine called The Vegetarian.
He died of colon cancer at the age of
Perhaps his diet some how
extended his life and he would have died at an even younger age had he
not been a vegetarian. This at least is a quite common argument I have
heard repeated by supporters of a vegetarian diet when one of their
proponents dies an early death. Ultimately there is no answer,
it is ironic that the person responsible for integrating a vegetarian
diet into what would become naturopathic medicine died so young of
According to Drs. McMahon and Williams, Henry
Lindlahr, the founder of "Scientific Naturopathy" in the
United States, "was
completely committed to vegetarian diet." Actually, the opposite
is true. In fact it has been
stated that Lindlahr often incurred the wrath of militant vegetarians
suggesting that "properly prepared and combined vegetables and
meats could be more wholesome than certain bad vegetarian
combinations." He wrote that it was not his intention "to make
a fetish of vegetarianism." Clearly he was not the strict proponent
of this diet that these critics would like to believe.
Dr. D'Adamo is far from the only
naturopath advocating a hunter gatherer-type diet for some people. The
work of Dr. Ron Schmid, ND in his books Native Nutrition and Traditional
Foods Are Your Best Medicine constitute some
best writings by an ND on the subject.
There may be a
repair mechanism that helps heal the intestinal lining from lectin
damage, but that does not constitute an effective argument for their
wholesale consumption. Put another way, our skin would also
eventually heal if we sliced it open with a
kitchen knife, but that is not a good reason to cut yourself.
ricin is from the castor bean, Ricinis communis,
not botulism toxin (as McMahon and
state above). Botulism is actually a bacterial toxin, not a lectin,
the Clostridium botuliinum. The rest
of the review is a hodgepodge of assertions, with many technical
errors (including an incorrect depiction of the rational behind the use of the urinary indican test to assess an individual's success with the diet)
and leaves us no purposeful way to respond.
Is it too much to expect a
critic with an agenda
to be possess a rudimentary level of knowledge in
the field they purport to criticize?
Often a good idea of the current tone of a Wikipedia article can be
gleaned from viewing the talk page for the entry.
Well-poisoning (opponents of alternative
medicine; naturopathic medicine)
It is very hard to provide relevant quotes
from the Wikipedia page on the Blood Type Diet since the entry changes
on an almost weekly basis. There is a tendency to highlight negative articles and
links about the Blood Type Diet while removing articles and links
supportive of the theory and using insider editor privileges to lock or block editing. Many of the negative entries are written by
special interest groups ('rational skeptics', 'guerilla skeptics') who are self-admittedly opposed to any form of alternative
medicine or scientific theories.
A clear sign of just how unreliable Wikipedia can be is the fact that the lead paragraph for what should ostensibly be an important entry on 'lectins' references 'Krispin's Lectin Story' a webpage compiled by a non-scientist entirely from third party sources that, rather incredulously, claims that the blood type diets 'are high lectin diets.'[retrieved 3/9/2012]
A main statement claims that "D'Adamo cites the works of biochemists and glycobiologists who have researched blood groups, claiming or implying that their research supports this theory. Nevertheless, the consensus among dieticians, physicians, and scientists is that the theory is unsupported by scientific evidence." provides links to external sources that are unrefereed, arbitrary comments, or opinion pieces. This fallacy is known as argument from authority, i.e "since certain selected experts disagree with the blood type diet theory, it must be wrong."
Extensive wordage is devoted to discrediting the theory (expounded in the most simplest of terms in Eat Right for Your Type) that different blood types appear to have developed their unique digestive strengths and weaknesses due to an adaptation over time to changes in the human food supply. In its most basic form, the theory posits that type Os may have developed their ability to metabolize and thrive on animal protein due to their being the most common blood group at the time humans were transitioning from a scavenger type type to a more hunter-gatherer diet. For years this was thought to run counter to conventional molecular genomics, due to the fact that blood type A is thought to be the so-called 'wild-type,' and that the mutations that resulted in different ABO blood types were in fact millions of years old.
'Previous studies indicated that B and O alleles were derived from A allele in human lineage. In this study, we conducted a phylogenetic network analysis using six representative haplotypes: A101, A201, B101, O01, O02, and O09. The result indicated that the A allele, possibly once extinct in the human lineage a long time ago, was resurrected by a recombination between B and O alleles less than 300,000 years ago.'
Paradoxically, the prior findings of the lead author of this article were the original citations used to refute Dr. D'Adamo's theory.
The Wikipedia design format does not typically work well with controversial topics. Typically, the victory goes to the most obsessed, which are almost always the skeptics. Walling off evidence that you find inconvenient to your world view is not how you discover the truth. The editors at Wikipedia are entitled to their opinions, but let's not confuse that with presenting factual evidence to the contrary.
The entry on the blood type diet, as with most entries on alternative medicine, are quickly stamped and categorized as 'pseudoscience.' This is a highly pejorative accusation, implying the lack of a sound scientific basis. Classifying the blood type diet as pseudoscience is not only intellectually dishonest, it violates Wikipedia's own definition of pseudoscience. Citations attempting to support the assertions of the editors that the diet has been 'discredited' have, at various times, included blogs and websites with no other justification than the author's particular opinions. Wikipedia needs to be reminded that a scientist with an opinion is not a scientific opinion.
Another example of Wikipedia's selective inclusion policy stems from arguments about the genetics and anthropology of the blood types:
Luiz C. de Mattos and Haroldo W. Moreira point out that assertions made by proponents of blood type diets that the O blood type was the first human blood type requires that the O gene have evolved before the A and B genes in the ABO locus; phylogenetic networks of human and non-human ABO alleles show that the A gene was the first to evolve. They argue that it would be extraordinary, from the perspective of evolution, for normal genes (those for types A and B to have evolved from abnormal genes (for type O).
Fair enough. In molecular history, type A appears to be the 'oldest' blood type, in the sense that the mutations that gave rise to types O and B appear to stem from it. Geneticists call this the wild-type or ancestral allele. The type B mutation is a simple replacement of one of the letters of DNA in the ABO gene with another; what geneticists call a snp (single nucleotide polymorphism) and everyone pronounces as 'snip.' The type O mutation is much more fascinating: It resulted from the complete loss of a letter in the ABO DNA and, like on a train when a boxcar is removed, all the other cars just move up by one. This type of mutation is called a frame shift and perhaps most amazingly, virtually every other known frame shift mutation is highly lethal. However, if you are type O, it made you.
However, although Type A is the genetic ancestor, it appears to have disappeared in humans a very long time ago, and then 'resurrected' itself about 300,000 years ago. This would be in accordance with the demographic evidence and would support a theory that hypothesized a more significant earlier presence for type O. (REF: Kitano T1, Blancher A, Saitou N. The functional A allele was resurrected via recombination in the human ABO blood group gene.Mol Biol Evol. 2012 Jul;29(7):1791-6])
Dr. D'Adamo spent most of 2007 getting his biographic entry removed from Wikipedia as it was an almost constant source of slander and innuendo. Sadly, Wikipedia has no clearcut policy to handle entries about live persons who oppose their inclusion. This was finally resolved by in a rather left-handed manner by lobbying to convince the Wikipedia administrators that Dr. D'Adamo was not a 'noteworthy person suitable for inclusion.'
throughout the internet, principally on vegan websites
The author is a medical
doctor. Dr. Klaper has not authored any peer-reviewed scientific
on blood groups or lectins. He has published several books on
vegan nutrition, principally for children.
Opposing diet theory (veganism)
of Eat Right For Your Type's
most disturbing characteristics is the frightening images that the
author calls forth without providing scientific documentation. For
example, D'Adamo hangs much of his theory on the action of lectins,
proteins found on the surface of certain foods that can cause various
molecules and some types of cells to stick together. He blames lectins
for serious disruptions throughout the body, from agglutination of the
blood cells to cirrhosis and kidney failure (page 24). He even scares
the reader about these lectin "boogie men" with the tale of ex-KGB
agent Georgie Markov who was murdered with an injection of the
ultra-potent lectin, ricin.
To begin to convince me of the existence of his “lectin gremlins,” he
would have to publish photographs, taken through a microscope, of
muscle tissue biopsied from people with Type O, Type A, Type B, and
Type AB blood after they have eaten kidney beans and/or lentils. The
photographs should clearly show the lectin deposits in the muscles of
people with Type O blood - and not in the tissue samples from the
muscles of people with Type A blood.
Remember, there is nothing sacrosanct about the ABO blood typing system
devised by Dr. Landsteiner in the 1920's. It is only one system
classifying more than thirty proteins on the surface of cells that
determine other blood groups, with names like Auberger, Diego, Duffy,
I, Kell, Kidd, Lewis, Lutheran, MNSs, P, Rh, Sutter, and Xg. This means
that food selections that may be "right" for the ABO blood group system
might be "dead wrong" for someone's Kell or Kidd antigens. Why are we
deifying the D-galactosamine-fucose molecules on the red cell surfaces
that determine ABO Type? "
Dr. Klaper's review features two basic logical fallacies: argument from incredulity or ignorance and argument by appeal to fear and emotions. He may want to
check his facts before he formulates his opinions. Lectins are
not found on the surface of many foods. They are an integral component
of the foods, principally found in grains, seeds and vegetable. The
carbohydrates they attach to (including the blood type antigens) are on
the surface of the cells of the body.
ricin tale were first described by DJ Freed MD, Head of Immunology
at the University of Manchester Hospital in Great Britain, in the
introduction to his chapter on lectins in Challcombe and Brostoff's
textbook Food Allergy and
Intolerance, and in his review article for the journal Lancet. It is common knowledge in
the scientific community.
"Every 30 seconds in this country, someone clutches their chest and has
a heart attack," Klaper said. "Heart disease is the No. 1 cause of
death in North America, and it's caused by atherosclerosis, which is
that yellow greasy stuff. But heart disease is reversible, and that
yellow greasy stuff will go away if you stop running animal fat through
your body. A meat-centered diet, he said, also upsets the body's
hormone levels and has been correlated to various forms of cancer."
Dr. Klaper's standards of proof are equally two-faced: He would like to
see muscle biopsies on lectin-munching test subjects, presumably type O
carnivores engorged on whole wheat bagels. Any compassionate scientist
could only be astounded by a silly paragraph such as this.
Biopsies no less! Any volunteers? No research study review board would
ever approve a study of this type. However, there are numerous studies
on MEDLINE which document the systemic effects of dietary lectins.
Dr. Klaper accuses Dr. D'Adamo of 'deifying' the ABO blood groups over
the others. This
is quite true, and there are numerous scientific
reasons behind it. For one thing, the other systems don't
manifest in the digestive
tract, nor appear to genetically influence the production of digestive
secretions. Only ABO is expressed outside the bloodstream, and in fact
is quantitatively expressed in greater amounts in digestive mucous than
on red blood cells. Here Dr. Klaper falls into the common trap of
professionals: They are simply unaware of the broader significance of
ABO blood type, as they were taught in school nothing more than its
importance with regard to transfusion.
Lansteiner discovered the blood groups in 1900, not the 1920's.
Sally Eauclaire Osborne, MS, is
currently completing requirements for the CCN (Certified Clinical
Nutritionist) credential with the International and American
Association of Clinical Nutritionists (IAACN). She has not
authored any peer-reviewed scientific papers
on blood groups, nutrition or lectins.
Opposing diet theory
(paleolithic; low carb)
"When we take a careful look at this theory
it appears a
bit "sticky." The majority of scientific studies linking blood types
and lectins have involved lectins added to blood isolated in test
tubes. But foods are NOT supposed to be injected directly into
blood stream. Mother Nature designed the digestive system to process
them for safe transport through the bloodstream and for easy
assimilation into our cells.
A healthy body with full digestive
and assimilative capabilities is completely capable of handling food
lectins. In fact, this is borne out by numerous studies which suggest
that lectins are either dismantled by enzymes -- which are abundantly
present in raw and fermented foods - or by cooking, which destroys the
helpful enzymes but compensates by denaturing complex proteins so that
they can more easily be broken down during the rest of the digestive
Few people today,
however, can boast fully functioning digestive systems. Two health
problems that have undoubtedly contributed to the ability of food
lectins to slip uninvited into the bloodstream are: widespread
hydrochloric acid (HCl) and trypsin deficiencies, which make it
difficult for people to properly digest protein, and "leaky gut"
syndrome, a condition in which large undigested or partially digested
protein molecules "leak" out of the GI tract and into the bloodstream,
where they do not belong and where they are likely to provoke an immune
Adelle Davis did not make a link between HCl
deficiencies and blood type; and Dr. Atkins does not consider blood
when he tailors programs to his clients, according to Joel Pescatore,
Ph.D., a nutritional counselor at the Atkins Center. So it is possible
that most of the people with this problem are all Type As or ABs, the
types Dr. D’Adamo feels are predisposed to chronic shortfalls of HCl.
The people with ample HCl may all be Type Os, as Dr. D’Adamo claims.
Yet the identification of age-related deficiencies coupled with reports
of failing health suggest a gradual decline of HCl over time. If so,
HCl deficiency is a preventable and correctable problem, regardless of
obvious conclusion is that proper soaking and cooking, and the use of
gelatin, can make the blood-type diets irrelevant. Type Os find they
can eat grains. Type A people -- whom Dr. D’Adamo believes are natural
vegetarians because they typically lack the abundant secretions of HCl
necessary for easy digestion of meats -- find meats easier to digest if
they are served with a gelatin-based gravy, stewed in their own broth
served along with a cup of soup. And gelatin can alleviate the allergic
reactions and sensitivities that numerous research studies have
connected to blood Types B and AB. Follow these simple, old-fashioned
rules and those pesky lectins will be dismantled in your healthy gut
never cause problems in the bloodstream. "
Like much of Dr. McMahon's criticism, Ms Osbourne's review suffers from the fallacy known as argument from incredulity (sometimes called "argument from ignorance").
In general Ms. Osborne seems quite new to
lectin material presented in the book, a fact that unfortunately
not inhibit her from writing about them. But
don't take my word for
Dr. D'Adamo has said this about Ms. Osbourne's review: 'Interestingly, a quick trip to
the anti-soy website that Ms. Osbourne writes for brings up the
interesting observation that one
should not consume soy because of its
dangerous hemagglutinating lectins. Now, it seems that when
I write about lectins, Ms Osbourne states that they can't get in
to the body. However when they can be used to support her
assertion that soy is a bad food for everyone, they apparently can
enter the body and do all sorts of harm.'
this advice, there follows a bizarre recommendation to use gelatin in
your food to block the effect of 'those pesky lectins'. In addition to
the fact that many people can not use gelatin for religious reasons, in
over 6 years of research we have never seen a single study to
support this contention. In fact many animal proteins, such as albumin,
enhance the reactivity of lectins.
This is a
completely unsupportable statement, with no basis in either
basic immunology or molecular biology. We only feel bad for those who
read it and think it is rational enough to employ.
After this paragraph, there follows
a long section of her review which tries to explain why the blood type
diet works, although in the beginning of her article Ms. Osbourne
she is one of several nutritionists who see "little or nothing that
clinically or scientifically supports the theory." Again, there
follows a long section of dietary advice with no particular relevancy
blood type at all.
The section talking about Adelle Davis and Robert Atkins makes even
less sense. Adelle Davis did not research blood groups. The head nurse
at the Atkins Center has in the past gone on record as stating that they
did have problems getting the diet to work with blood type A
Quackwatch is extensively linked throughout the
Stephen Barrett is a retired American
psychiatrist, author, co-founder
of the National Council Against Health Fraud (NCAHF), and the webmaster
of Quackwatch. Edward Blonz earned his M.S. and Ph.D. in
nutrition from the University of California at Davis.
Anti-alternative medicine; anti-naturopathic
"It may well turn out that there are important interactions with
between certain foods and one's blood type. D'Adamo, unfortunately,
offers little in the way of scientific evidence, relying instead on a
collection of anecdotal reports and case histories. His speculation
that the one gene responsible the ABO blood type could exert such a
dominant influence over everything else is unable to stand on its own
merits. In the end, D'Adamo adds the caveat that individual variations
still occur within blood types, so you shouldn't expect all of his
recommendations to apply to you. It's nice to have it both ways,
especially where book sales are involved."
"Critics of Alternative and Complementary Medicine (such as self-appointed "quackwatcher" Stephen Barrett) habitually employ this double standard. They will piously denounce alternative medical procedures for exceedingly rare adverse reactions, but ignore the fact that properly described conventional drugs kill over 100,000 in the US alone each year (Lazarou J, Pomeranz BH, Corey PN: "Incidence of adverse drug reactions in hospitalized patients." JAMA 1998;279:1200). They will condescendingly point to a lack of proper (i.e. double-blind) scientific studies supporting certain alternative procedures, and simultaneously ignore the fact that many conventional surgical procedures and drug protocols are equally unproven by the same standard. Worse yet, they will hold alternative medicine responsible for every case of malpractice that has ever been committed in its name, but they would not dream of applying the same standard to conventional medical practice."
Some other authors of non-recommended books include:
The Editors of Time-Life Books
The National Institutes of Health (NIH)
Ralph W Moss
Robert C Atkins, MD
Larry Dossey, MD
John Robbins (Robbins website makes extensive use of Klaper's article)
Andrew Weil, MD (see above)
Joseph Pizzorno, ND (founder of Bastyr University)
Deepak Chopra, MD
Herbert Benson, MD (Harvard University)
Dr. D'Adamo has commented in the past that "the only thing worse than
being included in the non-recommended reading list of Quackwatch would
be to have been left out."
Dr. Blonz's review doesn't really provide any tangible criticism.
the first two-thirds of the article appear to be more of a recitation
of the reasons why
would appear to influence diet.
The review contains much erroneous information, including
getting the number of genes in a human being wrong (humans have about
24,000 genes, not 150,000). Dr. D'Adamo's caveat about variations was
in regard to the added significance of secretor status, not some remark
about "individual variations and having things both ways." Dr. Blonz
appears unaware of the nontransfusion significance of blood groups:
ABO genes influence the a diverse number of body functions, from blood
thickness, to platelet function, to the constituents of the digestive
tract lining and much more. Perhaps if he were, he might have
written a better review.
Did not contact Dr. D'Adamo prior to article
Dated December 22, 1999, the Harvard affiliated Massachusetts General Hospital's Neurology Web Forum published on the Internet an article under the title :"PAC Money for Quackwatch". It reveals that "the FDA and the Pharmaceutical Advertising Counsel ("PAC"), which represents some 35 major drug companies, have formed and co-founded a corporation under a joint letterhead, calling itself the National Council Against Health Fraud ("NCAHF")." Stephen Barrett, MD, who publishes "Quackwatch" on line, William Jarvis, MD, and others, are paid by PAC " to publicly discredit as unscientific or unknown any of all viable herbs, vitamins, homeopathic remedies or non-allopathic therapies, particularly those that are proven to have the most promise and present the greatest threat to the PAC members". [link]
Currently Dr. Greger serves as the Director of Public Health and Animal Agriculture at The Humane Society of the United States. He is a major proponent of vegan-type, plant-based diets, which he proselytizes incessantly via internet videos. He is associated with various anti-low carb diet websites, including 'atkinsexposed.com' and 'nutritionfacts.org'
Philosophically opposed (carniphobe).
This small article is a tour-de-force of cherry-picked facts, all offered with a heavy dose of pre-interpretation and forgone conclusions. A careful reading of the critic's prior writings shows that he has a similar bias against other diets that involve any consumption of animal products. Dr. Greger self-produces many videos that are available on the internet. These have been criticized for their alarmist tendencies and elastic use of facts.
Professor Joe Schwarcz of McGill University recommends Greger's videos but says they contain "cherry-picking of data... Dr. Greger has swallowed the vegan philosophy hook, line and sinker; not that there's anything wrong with that. He promotes veganism with religious fervour and has forged a career speaking on health issues.
Skeptic and physician Harriet A. Hall has also criticized Greger's video 'Uprooting the Leading Causes of Death', saying his videos are part of a genre featuring "a charismatic scientist with an agenda who makes sweeping statements that go beyond the evidence, makes unwarranted assumptions about the meaning of studies, and omits any reference to contradictory evidence". 
Dr. Greger's skill at cherry-picking data has lead to some rather bizzarre conclusions, such as the idea that eating eggs will give you heart disease (a widely discredited notion.) Said one critic: 'Greger basically dredges up studies to back his conclusion that a vegan diet (with vitamin B12 supplements) is the way to go. That's fine for him to believe and promote, but it leads to some rather comical statements as he pushes his orthodoxy.' [3,4]
In his blood type diet debunking article, which is filled with ad hominem type attacks and non-sequiters, we are advised that a study 'in one of the most prestigous nutrition journals 'looked for evidence of the blood type diets and did not find any.' This is offered as proof of their lack of validity, when in fact all the article said was that there were no studies found that had examined the blood type diet and that they should be undertaken. The rest of the critique is a mash-up of assertions about various unrelated aspects simply drawn into the argument to call my credibility into question, but having nothing to do with the scientific basis of the blood type diets, which he virtually ignores. All of these assertions have been answered at one time or another, often on the exact same web pages where Dr. Greger got the information in the first place.
Dr. Greger is extensively linked to the Humane Society of the United States, an organization with questionable ethics. Worth magazine gave HSUS a 'D' rating for spending as much as 53 percent of its expenses on fundraising, and which had been described as a 'A sprawling institute for animal rights masquerading as an animal-welfare charity.' 
With his pronounced vegan biases, depending on Dr. Greger to provide an unbiased assessment of the Blood Type Diet is the approximate moral equivalent to relying on an umbrella salesman for meteorologic data and future weather forecasts.