Nov 09 2011

When you point one finger, four usually point back at you.

There have been no shortage of supercilious, poorly researched articles about the blood type diets in the major media. They are usually provoked by a statement of support by some celebrity or media icon who has experienced success with the plan. Typically within a week my phone rings off the hook with one major media outlet or another needing ‘to talk with me as soon as possible because we are doing a story on your diet and are on deadline.’

This rushed approach characterizes almost every encounter I’ve had with major media. They gobble up whatever simple facts there are so as to explain the gist of the story, then go looking for an opposing viewpoint so they can get off being held responsible for any direct conclusions. This is called ‘balanced journalism.’

The article usually begins with a roll call of all the famous people who are following or have been on the diet. I usually have never heard of any of these folks, but my daughters often serve to tell me a bit about who they are. Then the diets are described, but never fully. Some reporters concentrate on the lectin-blood group specificity, others the anthropology, some the digestive differences in physiology. However, I’ve never seen a single article explain all aspects to some degree, which is of course the strongest argument for the theory: That it can be verified in multiple dimensions of analysis.

On the positive side, many articles feature a personal story about an average-type person who has had success with the diet. Usually the focus is weight loss, for obvious reasons. Very few of these articles profile people who have been cured of any physical diseases by adopting this way of eating. Again, this is due to legal issues. However, trying to heal or control a physical illness is the most common reason why people try the blood type diets.

Hard Facts from the Fiction Department

Finally, and this is almost always rolled out at the end, the article presents one or two nutrition experts to pass judgement on the merit, risk and need to follow a diet for your blood type. Unless the expert has had some exposure to the deeper, scientific basis for the theory (never) their comments are almost universally negative.

These comments usually fall into common categories:

  • The diets are dangerous. This statement is usually proffered by experts concerned that, by restricting certain foods by blood type, people will develop nutrient deficiencies. However, each diet variant (A, O, B and AB) is a carefully engineered balance of foods that ensures full nutritional value. This criticism has a long and hallowed record of institutional whoring for agribusiness: ‘whole grains are fine, except if you are gluten sensitive’, ‘high fructose corn syrup can be part of a balanced healthy diet’, etc. Curiously, this concern is often matched with the next:
  • Of course people get better, the diets are all healthy: If you tell someone to get off of diet soda, they will feel better. I actually have no problem owning this criticism. We do include a lot of good naturopathic food wisdom with the blood type recommendations. I fail to see the problem with that. Paradoxically, if one were to go back and read my earliest popular book, Eat Right For Your Type they would find perhaps some of the earliest references to the value of using grass-fed beef, spelt and sprouted breads, quinoa and amaranth grains and a host of other weird foods. Now these are all part of the popular culture, but back then nobody recommended these things. I’ve always thought that the basic benefit of using blood type as a guide to proper eating was its ability to let people know exactly which, of all the supposedly healthy diets, would be best for them.
  • There is no scientific validation. This criticism is particularly nefarious, since it says one thing but means another. To say that the blood type diet theory has not been tested in large numbers, via a double-blind study, at some neutral university, is in fact true. There are reasons why this has not occurred. One is the sheer size and cost of a study of this sort. Food and diet studies are notoriously difficult to control, require constant supervision, often must be pursed for years, and are enormously expensive. Now, on top of all that, multiply the work and expense by four. But let’s talk about what this criticism actually means. Most of the time what the critic is really implying is that the theory has no scientific basis, which is a form of intellectual dishonesty, since not one of theses critics has ever taken the time to read through the extensive collation of existing research, much of it freely available online, that supports the conclusions drawn to form the basis of the blood type diet. I don’t spend a lot of time writing critiques of other diet theories, but if I was planning to do so, I’d probably pick up the phone, call the other guy, explain my concerns and see if I’d gotten my facts straight. Yet in the last fifteen years I’ve never received any such phone call.
  • This is pseudoscience. This pejorative term is often used in conventional science to tar and feather ideas and practices that have no basis in accepted science, such as a theory that flouts the basic laws of physics. Of course, one man’s pseudoscience is another man’s frontier science, but that is the continual rub of forward progress and most honest scientists agree that it is part of the game. However, usage of the term has increasing become a favorite tactic of scoundrels to manufacture disinformation and stop interest and inquiry into a topic they might detest for any number of non-scientific reasons. By the way, there is nothing in the theory behind eating for your blood type that flouts the laws of physics, chemistry, immunology or physiology. On the contrary, that’s the problem: To talk intelligently about it requires that you know more than a little about these disciplines.

Case History

My office was recently contacted by Alexia Elejalde-Ruiz, a young reporter for the Chicago Tribune and told that they were doing an article on the blood type diet. Having given literally hundreds, if not thousands, of interviews at this point, my PR person usually begins the process with a few questions, such as what prompted the interest. In this case the interest appeared to stem from the health editor, who is apparently a type O vegan and somewhat distraught by the conclusions drawn from my theories. However the reporter was respectful and several emails went back and forth with the aim of addressing concerns from some of the nutrition experts. Since some were quite technical we directed the reporter to various links that discussed those point in detail. However, none of our corrections were turned into teaching points (for example, ‘a lot of people often think this about the diet, but in fact..’). Instead it seemed that they just went down their list to the next concern.

My Spidey senses were tingling, and I suspected that the article already had a preconceived agenda. Not surprisingly, when released the article pretty much went out of its way to diss the entire concept. Because of an association with Gannett Publishing, this article has appeared in other publications as well.

Famously, one of the experts firing the dreaded Parthian Shot, a Michael Greger, MD, who is touted as the head of something called, was quoted as the following:

Dr. Michael Greger, founder of, said the premise of the blood-type diet is wrong: The blood-type system, which predates humans, is far more complicated than just ABO, he said. “People crave individualized, personalized science, but this is pseudoscience,” said Greger, a general practitioner specializing in clinical nutrition.

I will not dwell on the stupendously ignorant basis of Dr. Greger’s criticism, since it betrays a complete lack of understanding about how blood types function in the body. You can read my answer to a similarly uninformed vegan doc here. What is interesting is the use of the pseudoscience label. Not simply because it is being applied by a person ignorant in the basic science, but rather because a quick look at Dr. Greger’s website ( and his ostensibly important job as head of the rather questionable show instead a vegan-biased, rather jaundiced army of one, and certainly not the vaunted expert the Tribune article purports him to be. Although I certainly acknowledge the value of vegan diets for some people (but certainly not everyone) others argue that the vegan diet theory itself is a pseudoscience, hence the title of this blog.

Conclusions, if any.

Media profilers of science and health need to start vetting their so-called experts. Here’s a news flash: Many critics of diet books have their own diet books and dietary agendas to protect. You’d think as professional news media this would cross their minds, but apparently it doesn’t. Balanced journalism should not mean that you just go out and find someone to disagree with the premise of your coverage.

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