Did You Know…the blood type diet is built on lies?
The blood type diet is one of the most interesting examples of how you simply cannot believe everything you read, no matter how compelling it may seem, or how popular the message becomes. When Dr. Peter D’Adamo first published his book Eat Right for Your Type in 1996, it quickly climbed to the top of bestseller lists. The central premise of the book (written with collaborator Catherine Whitney) is that your blood type determines which foods are best for you to eat.
According to the book, each type responds in its own unique way to diet, exercise, vitamin supplements, and so on. The idea that our blood types constitute evolutionary markers that can guide our nutrition and exercise choices is interesting. It’s also completely untrue.
“No Evidence” That Blood Type Diets Work
In 2013, a systematic review of all studies supporting the blood type diets was published in one of the foremost nutrition journals in the world. The researchers analyzed over 1,000 scientific papers on the blood type diets, and found zero association between the diets and health-related outcomes. “There is currently no evidence,” they concluded, “that an adherence to blood type diets will provide health benefits, despite the substantial presence and perseverance of blood type diets within the health industry.”
The 2013 review was not the first to come to that conclusion. A decade prior, the Norwegian Society for Nutrition held a day-long seminar specifically to determine whether the blood type diets were based in good science. The Journal of the Norwegian Medical Association released a number of papers drawing from that seminar, all of which found unequivocally that blood type diets were nonsense.
Author Challenges Scientific Findings
Not only does D’Adamo refuse to concede, he is actively challenging these findings. According to D’Adamo, the science behind his diets holds up when tested the right way. Such studies have not been carried out due to “little interest and available money.” Little money? He’s sold more than 7 million books! Surely he can afford to fund studies of his own, as the Atkins Corporation did.
Turns out, he may have done just that. At the time of the release of his first book, he said: “I am beginning the 8th year of a 10-year trial on reproductive cancers, using the Blood Type Diet… By the time I release the results in another 2 years, I expect to make it scientifically demonstrable that the Blood Type Diet plays a role in cancer remission.” But 16 years later, D’Adamo has yet to make good on the proof.
He has tried to repeat that same tactic, however, of citing pending tests that will vindicate the blood type diets. In 2005, he reported that he was conducting a “12-week randomized, double-blind, controlled trial implementing the Blood Type Diet to determine its effects on the outcomes of patients with rheumatoid arthritis.” Once again, any results this supposed trial might have turned out have yet to be published.
The bright side of all of this is that a popular diet book was so thoroughly fact-checked—a rare occurrence, to say the least. Perhaps if more diet and lifestyle guides were scrutinized like this one has been, fewer people would waste precious time and money on plans that just don’t work.