Things You Should Know About Blood Type Diet

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Ever heard of the concept “Blood Type Diet”? Well, now you do. It is a diet that has been popular for almost two decades now.

Proponents of this diet suggest that your blood type determines which foods are best for your health. And there are many people (especially in the West) who swear by this diet, and claim that it has saved their lives.

But what is blood type diet really? What does science say about it? Are there evidence supporting its proponents claim?

Let’s find out.

What is The Blood Type Diet?

The blood type diet, also known as the blood group diet, was popularized by a naturopathic physician called Dr. Peter D’Adamo in the year 1996.

His book, Eat Right 4 Your Type, was a tremendous success. It was a New York Times bestseller, sold millions of copies, and is still wildly popular today.

In this book, he claims that the optimal diet for any one individual depends on the person’s ABO blood type.

He claims that each blood type represents genetic traits of our ancestors, including which diet they evolved to thrive on.

According to Dr. Adamo, here’s the diet plan for every blood type:

  • Type A: Called the agrarian, or cultivator. People who are type A should eat a diet rich in plants, and completely free of “toxic” red meat. This closely resembles a vegetarian diet.
  • Type B: Called the nomad. These people can eat plants and most meats (except chicken and pork), and can also eat some dairy. However, they should avoid wheat, corn, lentils, tomatoes and a few other foods.
  • Type AB: Called the enigma. Described as a mix between types A and B. Foods to eat include seafood, tofu, dairy, beans and grains. They should avoid kidney beans, corn, beef and chicken.
  • Type O: Called the hunter. This is a high-protein diet based largely on meat, fish, poultry, certain fruits and vegetables, but limited in grains, legumes and dairy. It closely resembles the paleo diet.

It is noteworthy that these dietary patterns would be an improvement for most people, no matter what their blood type is as all four diets are mostly based on healthy foods. Basically, even if you go on one of these diets and your health improves, it doesn’t necessarily mean that it had anything to do with your blood type.

Maybe the reason for the health benefits is simply that you’re eating healthier food than before.

Topping it all, the type A diet resembles a vegetarian diet, but type O is a high-protein diet that resembles the paleo diet. The other two are somewhere in between.

Lectins: The Link Between Diet and Blood Type

The theory behind Blood Type Diet revolves around the assumed connection between a protein called lectins and agglutination in the blood. Lectins are a diverse family of proteins that can bind sugar molecules.

These substances are considered to be antinutrients, and may have negative effects on the lining of the gut. And according to the blood type diet theory, there are many lectins in the diet that specifically target different ABO blood types.

It is claimed that eating the wrong types of lectins could lead to agglutination (clumping together) of red blood cells.

There is actually evidence that a small percentage of lectins in raw, uncooked legumes, can have agglutinating activity specific to a certain blood type. For example, raw lima beans may interact only with the red blood cells in people with blood type A.

Overall it appears that the majority of agglutinating lectins react with all ABO blood types. So, what?

It means that lectins in the diet are NOT blood-type specific, with the exception of a few varieties of raw legumes. This may not even have any real-world relevance, because most legumes are soaked and/or cooked before consumption, which destroys the harmful lectins.

At the bottom of this all, we can say that some foods contain lectins that may cause red blood cells to clump together, BUT MOST lectins are NOT blood type specific.

Is There Any Scientific Evidence Behind The Blood Type Diet?

There are plenty of scientific resources on ABO blood types. In fact, research on ABO blood types has advanced rapidly in the past few years and decades. There is now strong evidence that people with certain blood types can have a higher or lower risk of some diseases.

For example, type Os have a lower risk of heart disease, but a higher risk of stomach ulcers (Evidence 1, Evidence 2). However, there are no studies showing this to have anything to do with diet.

In a large observational study of 1,455 young adults, eating a type A diet (lots of fruits and vegetables) was associated with better health markers. But this effect was seen in everyone following the type A diet, not just individuals with type A blood.

Moreover, in a major 2013 review study where researchers examined the data from over a thousand studies, they did not find a single well-designed study looking at the health effects of the blood type diet.

Their conclusion? “No evidence currently exists to validate the purported health benefits of blood type diets.”

One of the studies that found a relationship between blood types and food allergies actually contradicted the blood type diet recommendations.

Take Home Message

There is no doubt that following the prescribed diet plan according to blood type in Dr. Adamo’s Blood Type Diet plan will produce positive results. But this does NOT mean that this was in any way related to their blood type.

It is noteworthy that these dietary patterns would be an improvement for most people, no matter what their blood type is as all four diets are mostly based on healthy foods. Basically, even if you go on one of these diets and your health improves, it doesn’t necessarily mean that it had anything to do with your blood type.

Diets are not created equal. What works for some, might not work for the others, and vice-versa. If you got great results on the blood type diet, then perhaps you simply found a diet that happens to be appropriate for your metabolism. It may not have had anything to do with your blood type.

That being said, if you went on the blood type diet and it works for you, then by all means keep doing it and don’t let this article dishearten you.

If your current diet ain’t broken, don’t fix it.

From a scientific standpoint, however, the amount of evidence supporting the blood type diet is particularly underwhelming.


1 “The Blood Type Diets: Dr. Peter J. D’Adamo.” 2015. 10 Mar. 2016 <>

“ABO blood group system – Wikipedia, the free encyclopedia.” 2011. 10 Mar. 2016 <>

Adapted from his book.

“Antinutrient – Wikipedia, the free encyclopedia.” 2011. 10 Mar. 2016 <>

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