Dr. D’Adamo published the book Eat Right 4 Your Type (aka The Blood Type Diet) in 1996. In nearly two decades Dr. D’Adamo sold over 7 million copies of his book and had it translated into 65 languages. He’s been recognized with awards and accolades with his take on improving one’s health using a diet based on your blood profile. With this much recognition and testimonials claiming it’s a miracle diet one would think it’s the end all, be all of diets. But, is it the magical diet Dr. D’Adamo claims it to be?
To be fair I gave the blood type diet a try a few years ago. While this wasn’t a perfectly planned study I did adhere to the diet recommendations (I’m type O+). The diet recommended was very similar to a Paleo diet. At the time I was following a strict Paleo diet so it wasn’t difficult to adjust. During the 8-week ‘trial’ I didn’t notice any significant changes in my health, good or bad. Perhaps, since my current diet was so similar I was already reaping the benefits of a diet based on my blood type. Or, I was fairly healthy to begin so maybe there wouldn’t be much change at all. Having little change I just kept eating the way I had always eaten. It wasn’t until recently that I came across someone who was following the The Blood Type Diet and claimed the health benefits to be real. This peaked my interest and I took another look at this diet and wanted to know if any studies were conducted relating to blood type dieting and overall health improvement. There were!
A group of researches analyzed over 1,400 studies related to dieting and had 6 criteria that needed to be met in order for a study to have any validity. Over 1400 studies were narrowed down to 16, then 4, then 2, then 1. The final study did show an improvement in cholesterol levels but it was unrelated to blood type. The researches reported their findings to the American Journal of Clinical Nutrition. Their report stated there was zero evidence, I repeat, ZERO EVIDENCE to support eating a diet based on your blood type will improve your health.
While the person I spoke with recently claimed they saw improvements in their health I would have to look at their diet prior to starting a blood type diet. If they’ve been following a poor diet filled with processed foods, grain-fed beef, high amounts of sugar, etc. then perhaps their diet saw an improvement from simply reducing these food sources from their diet. On the other hand, this person might have been following a healthy diet but making a few adjustments based on what Dr. D’Adamo recommended could have shown some benefits. That’s up for you to decide. What isn’t up for discussion is Dr. D’Adamo’s lack of evidence to support his claims. They don’t exist.
Since 1996, Dr. D’Adamo has stated he will conduct both a 12-week and 2-year study to prove his theory that a blood type diet can improve your health. That was nearly 20 years ago and guess what? No studies have ben conducted. You’d think with over 7 million books sold he’d have the finances to complete his study by now. He hasn’t. We’re waiting Dr. D’Adamo.