Despite numerous attempts by many people to let Dr. Andrew Weil know that his traditional criticisms of the Blood Type Diet have no basis in fact, he still insists on peddling his absurd take on my work. In a recent interview for a Canadian website, Weil repeats the same criticisms he has used for the last ten years --despite the fact that they are as inaccurate and ignorant of the basic facts now as they were a decade ago.

Among other things, Dr. Weil says:

This is nonsense. I know of no evidence suggesting that prehistoric people ate diets related to their blood types. The studies D'Adamo cites have been published only by him and not in any scientific journals. By the way, dogs and other animals have blood types similar to those of humans. It would come as unwelcome news to some dogs that they should be vegetarians.

This tone suggests to me that Dr. Weil has not actually read any of my books.

I've never suggested that prehistoric people ate diets according to their blood types. No doubt they should have, but how would they have known? The blood groups were not discovered until 1900.

I have suggested that the variations in our different digestive physiologies stem from adaptations over time to changes in diet that were in part coded by the immunology that governs the gut. And that this immunology is significantly under the influence of ABO blood type.

Dr. Weil avoids or just plain neglects the physiologic links between digestion and ABO blood types. This lets him parody my theory as some sort of 'caveman-fiction.' The effects of secretor status on immune and metabolic function; the connection between lectins and allergies; the influence of blood type on intestinal enzymes; links between stomach hydrochloric acid levels and gut bacteria; the fact that the very foods we eat have 'blood types' --all of this receives no mention.

These findings and facts are part of over 7,000 peer-reviewed studies on blood groups published in the medical literature over the last century. Now, I know that allopathic (MD) education does not teach any of this, so I don't blame Weil for being initially uninformed. Everyone has got to start somewhere. However he does not exhibit any curiosity on the subject nor a desire to investigate it any further. If he'd have contacted me, I'd have probably shared them with him. Instead we're left with the rather smug assumption that since he's never heard of any of this, it must not exist.*

Folks, that is an attitude that they usually do teach you in allopathic medical school.

I've always gotten a kick out of his "Well, animals don't eat right for their type" argument. If he knew the species genetics of ABO blood groups he might be surprised to learn that the ABO gene locus resides on different chromosomes in the various species. In hogs for example, having type O blood gives you a full coat of black hair. By Dr. Weil's account, every human who is type O blood should also have black hair. Dogs, by the way, are a very cancer prone species, and do fare much better on something other than an exclusively carnivorous diet.

Sigh.

The late Arthur C Clarke said it best in his First Rule of Scientific Prediction:

When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

* Dean Ornish repeats a similar mantra to audiences that he is 'unaware of any studies linking heart disease to blood types', when even the most cursory of searches on MEDLINE would show 200+ articles since 1966 (and probably over 300 from 1950).

This week's TIME magazine featured an execrable perspective on The GenoType Diet courtesy of columnist Andrea Sachs. In a column called Calorie Countdown she treats TIME readers to an array of her opinions on the various 'notable diets of 2008.'

The GenoType Diet gets short shrift from the pen of Ms. Sachs. In an analysis which appears to me no deeper than the back cover of the book's dust jacket (while also deriving substantial inspiration from The Fifth Dimension) she writes:

By Dr. Peter J. D'Adamo, with Catherine Whitney (Broadway; 317 pages). Naturopathic physician D'Adamo has identified six "GenoTypes"--the Hunter, the Gatherer, the Teacher, the Explorer, the Warrior and the Nomad--and gives food dos and don'ts for each. The book comes off about as scientific as telling Scorpios they should eat only food grown when Jupiter aligns with Mars.

Trying to learn more about who writes this type of article for America's most beloved weekly illustrated magazine, I retrieved this biography off the TIMES.com site:

Andrea Sachs is a former English major whose dreams were fulfilled when she became TIME's publishing reporter in 1995. What could be better than interviewing authors, reading fabulous new books, and going to publishing parties?

I guess Goethe was right. You do see what you know. Ms. Sachs never interviewed me, and seems to have not actually read my 'fabulous new book.' As far as the parties... well.

Some people seem to just get things wrong. One can only suppose that in world of Andrea Sachs I actually think that the universe splits up into Teachers and Nomads and that Teachers should teach stuff and Nomads should wander around. Those are just memes. Science writers often do this in an attempt to bring complex characterizations to life for laymen. That, as any good English major should know, is called a literary device. Read The Seven Daughters of Eve by Brian Sykes for a similar treatment. In the last third of the book Sykes writes narratives about fictional clan mothers ('Helena', 'Tara', etc.) which correspond to one (or more) human mitochondrial haplogroups.

A friend of mine was fond of saying that "You can always spot the pioneers. They are the folks with the arrows in their backs."

Now, that's real science.

*. The phrase 'file under futile' is from 'Back In Judy's Jungle' by Brian Eno

It's interesting to gauge the expert reactions to this diet theory. A lot of professionals, including a few naturopathic colleagues, seem to think that they have to abandon every long-held notion to accept (or maybe allow) this idea to penetrate their thinking.

Personally, I think this is wide of the mark. The BTD and the GTD are concepts that can be used in a wide variety of permutations, certainly much more than simply determining a person's blood type and giving them diet advice.

Perhaps if they just relaxed their shoulders and bit and slowly exhaled, they might discover that the idea really doesn't require you to 'Drink the Koolaid'.

As my colleague Dr. Natalie Colicci said to me the other day, 'these are all healthy, whole foods diets... with perhaps the added value of having a better than average benefit in some folks versus others.'

The etymology of pathos, pathetic and pathological are all the same. They come from the Greek word ('pathologia') that is the name for the study of emotions.

Can you judge a book by its cover? What about if you don't even have a cover?

Recently my publisher leaked a tidbit about The GenoType Diet to one of those glossy woman's magazines. In an article of perhaps two whole paragraphs the editors chose to mention my book and another one I had never heard of as two of the new books on genes and diet.

Anyway, after a quick trial and summary execution from the resident expert, the reader was essentially advised to read the book not written by me.

Now, in case you don't already know, virtually all the women's magazines are the lock and stock domain of organization shills for professional nutrition associations, which is why the advice in these ad-driven magazines is so generic and inoffensive. Though they act the part of impartial consumer advocates, most glossy womens magazines are in the diet business themselves, usually cranking out a 'new' one with every issue.

I doubt that the resident experts ever laid eyes on a copy of The GenoType Diet. The manuscript wasn't ready in time to send them a galley copy.

So here we are. 'Experts' now tell us to avoid reading something they've never read.

1.

An associate of mine, an amateur skeptic with professional zeal, says that without telling me he was acting on my recommendation to look into the Eat Right 4 Your Blood Type books, found that Dr. D'Adamo denies wheat to all four blood types in his recommendations, a little feature I hadn't picked up on. "Therefore, he's just another quack, and can be disregarded." While even if the 4-type denial is true, which I haven't checked out for myself yet, having just had this conversation, I feel a little more sympathy for it, being someone with celiac sprue. My associate, however, won't admit he has psoriasis! He said if I used that word again in talking with him, he would never communicate with me again. I was hoping to edge him toward some empirical improvement with the blood type diet, but that was ended by the hammer-fall of his judgment, at least for the present. -Peter

Hi Peter,

I'd have your friend check the book again. His calculations are off.

If we look at whole wheat

Total incidence of type A secretors = 34.2%
Total incidence of type AB secretors = 1.7%

Total percentage of the population in which whole wheat is at least 'neutral' is 36%

If we look at spelt wheat

To find the total percentage of the population in which spelt wheat is a least 'neutral' (an avoid only for type O non-secretors; about 8% of the population) is even easier. Spelt has a higher mucopolysaccharide and lower gluten content that whole wheat, which may help modulate its pro-inflammatory proteins a bit, I think.

Subtracting that serotype leaves about 92% of the population (perhaps; there are other possible reasons against) who can use spelt type wheat.

However, these numbers may be optimistic: evidence suggests that our sensitivity to gluten containing foods is on the rise.

I think we will see many possible correlations between the diseases of industrialized society (such as diabetes and obesity) and their current wheat and corn based diets.

2.

I have happened across a book I think will be of interest to you. Have never seen a reference to this on the message board. It's called 'Eat to Live', by Joel Fuhrman M.D. The book is on diet and weight loss but has a 7 page piece - critique of the BTD. At least this guy did a bit of research. -Thanks Bruce.

Hi Bruce,

Maybe you should bring it up on the Forums and see what kind of discussion ensues.

I've don't know Dr. Fuhrman and have not come across his name in any of the research areas of biology and genetics that I study. I'd like to see him stick to his own projects rather than find the time to inveigle his readers with tales and criticisms of his competitors.

There was a wonderful TV program on Isaac Newton the other night. It seemed (at least to me) that every time Newton announced a new discovery --the polychromatic nature of light, the reflecting telescope, Calculus-- this other guy (whose name I forgot) would write a critique simultaneously claiming that Newton was wrong and he that had discovered this earlier anyway. Newton apparently got seriously bent out of shape by these types of shenanigans.

Stephen Jay Gould had an interesting take on this, as part of a response to criticisms of his theory of 'Punctuated Equilibrium' (1):

THE MOST UNKINDEST CUT OF ALL. If none of the foregoing charges can bear scrutiny, strategists of personal denigration still hold an old and conventional tactic in reserve: they can proclaim a despised theory both trivial and devoid of content. This charge is so distasteful to any intellectual that one might wonder why detractors don't try such a tactic more often, and right up front at the outset. But I think we can identify a solution: the "triviality caper" tends to backfire and to hoist a critic with his own petard—for if the idea you hate is so trivial, then why bother to refute it with such intensity? Leave the idea strictly alone and it will surely go away all by itself. Why fulminate against tongue piercing, goldfish swallowing, skateboarding, or any other transient fad with no possible staying power?

Gerhard Uhlenbruck, one of our IfHI speakers, says it differently:

Never chase a lie. Let it alone, and it will run itself to death.(2)

I have my own aphorism to add:

Negative reviews of popular diet books are too often found inside of other popular diet books.

I'm actually flattered that someone would go to the trouble of writing a seven page refutation of my theory. However, I don't have the time or energy to write a seven page reponse, so this must do.

But finally, I leave you with the words of my Tang Soo Do Sa Bom:

You want to show me something you've read? Great. Get out there on the floor and show me.

(1) Stephen Gould 'The Structure of Evolutionary Thinking' (2002) Belknap, Harvard Unveristy Press.

(2) Gerhard Uhlenbruck on The Individualist.