Interesting Stories

The Blood Type Diet – The Battle of the Debunkers

Diets are a point of conflict for me. There’s the side of humanity that is starving and would kill for food, and the side that is starving and craves attention. But its diets like the Blood Type Diet that make me laugh so hard I nearly broke my belt. Not because of the diet itself (it has actually helped some people), but because of the person who is pioneering it, and the squabbles he has faced since he released his book “Eat Right 4 Your Type.” And I’m going to tell you the story.

Once upon a time…

  • 1996 – “Eat Right 4 Your Type” Published by Peter J. D’Adamo

    Our story begins with the naturopath doctor Peter J. D’Adamo publishing his first book, which immediately climbed up to the New York Times Best Seller list. This was only 6 years after being awarded with Physician of the Year by the American Association of Naturopathic Physicians. So one can imagine the hub-bub that erupted in the diet-crazed community, to have a new diet plan, by an established physician! And for those who are unaware, naturopathy is defined by Lexico as “a system of alternative medicine based on the theory that diseases can be successfully treated or prevented without the use of drugs, by techniques such as control of diet, exercise, and massage.” According to JoAnn Yenez, a naturopathic physician, there are two ways to become a naturopathic doctor, and that is through “online programs” or “accredited four-year naturopathic programs.”

  • 2000 – Consumers Rave About the New Personalized Diet Plan

    After his book was released, many of his readers loved the content because of the “individualized opportunities” it offered, as stated on D’Adamo’s website. The appeal appeared to come from the unique plans it offered to each individual who read and took the diet seriously. Everyone has a different genetic makeup, a different blood type – find your unique diet today! Reviews of the book from 2000 ranged from glowing positive reviews, as one reviewer puts it, “After just a few days avoiding the foods the diet says aren’t good for my blood type, I noticed a change. I started feeling better. I had more energy.” This side of the story makes sense to me, I have experienced the same phenomenon! Whenever I finally decide to get up off my couch and eat a home cooked meal instead of my usual potato chips with ice cream a la mode, I also feel much more energetic. Healthy foods are nuts like that.

    While some gleaned positive revelations about their health and energy levels, others reacted differently. “In 30 days, my energy and strength waned, my appetite increased, I gained 10 pounds and I fell very fatigued and over-carbed.,” as stated by Stands With A Fist in a review on Amazon.

  • 2014 – The University of Toronto Debunks the Blood Type Diet

    The University of Toronto released a scientific study based off of D’Adamo’s book, and their goal was to test his claim that “an individual’s nutritional needs vary by blood type.” And this is where it gets juicy. The U of T concluded that “the theory behind the popular blood type diet … is not valid.”

    Now, if evidence-based medicine (EBM) is Luke Skywalker, then naturopathy is Darth Vader, the way they carry out studies are completely opposite. Though some naturopathic remedies align with evidence-backed medical findings, the theory is based in energy and philosophy — which is not scientific (yet?). Scott Gavura, an opposer of non-evidence based medicine, phrases it this way, “Given there’s no requirement to justify or rationalize practices in scientific terms, pretty much anything goes, as long as it aligns with the underlying philosophy.” This type of thinking brings me back to my childhood, where I was taught that if you believe something hard enough, you can make it true. It’s not evidence based, its based on the philosophy you want to be true. That’s all fine and good, but when it boils down to your health, I believe that you need reality based, time-proven evidence to help you live the longest life possible.

    The senior author of the study, Dr. Ahmed El-Sohemy, did not say that he thought the diets were not beneficial, just that the diets did not depend on blood type, but rather the participant’s “… ability to stick to a sensible vegetarian or low-carbohydrate diet.” It seems to me like El-Sohemy was trying to get to the bottom of the same question D’Adamo himself was trying to answer; which was how each human’s individual makeup favors one diet over another.

    However, I don’t think D’Adamo took it quite that way.

  • 2018 – D’Adamo Releases Counter Study Against El-Sohemy

    After reading the sobering study conducted by Dr. El-Sohemy, I decided to look through D’Adamo’s website to see if he had anything to say about the study.

    I was not disappointed with what I uncovered.

    I could not find an official publishing date for D’Adamo’s counterattack. However, I’m guessing he carried out the “study” in 2018, judging by the latest data point he graphed in his report. I have never before seen such a spectacle in the scientific community. The report published was absolutely riddled with subjective language, spelling, and grammatical errors. Now, I’m no expert scientist (though I do dabble), but I know that all of the aforementioned are practically forbidden in the respectable scientific community.

    The basis of D’Adamo’s argument was El-Sohemy not using every single food mentioned in his book (A total of 540!). This led to D’Adamo “debunking” the “debunked” study… stating avidly that El-Sohemy’s study did not accurately represent the food values he described in his book. Under normal circumstances, I would be inclined to believe the victim in this situation, the underdog who just wanted to help people with his new, fresh, individualized take on the common diet plan…


    When one starts their discussion (concluding) paragraph of their scientific report with, “It is well-worth wondering how a study with such basic flaws in its design could have survived peer-review.” I can’t help but imagine a teenager trying to get revenge on their ex.

In conclusion, the Blood Type Diet was (and is) a very specialized diet, helping some, and harming others. Peter J. D’Adamo is a very persistent and fervent believer in his practice, but belief is not proof. Science is about logic; building up our collective knowledge-base through trial and error, acknowledging when we’re wrong, and moving on with a better understanding of the world. I understand wanting something to be true, believing that “it” could come true, but I draw the line at believing so hard you become a slave to delusion. This is especially important in the medical field, because any person only gets one chance to live, and this has created a fine line. A line where life and death are allowed to coexist, and dance around on each of our individual fates.

In no way am I saying that D’Adamo or El-Sohemy did anything wrong. Every human on this planet makes their own choices. My point is: What would you prefer that fateful dance be choreographed by, evidence-based science? Or a pretty strong hunch?

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