It has already been over two decades since the release of naturopathic physician Dr. Peter D’Adamo’s book ‘Eat Right For Your Type’ in which he introduced ‘The Blood Type Diet’, and yet, over twenty years later, his diet strategy is becoming increasingly popular, and some would say for good reason, but is this diet all it’s made out to be?

Due to the fact that the health and fitness industry has a lot of grey areas when it comes to training, supplementation, and nutrition, there is a multitude of individuals and companies whose aim it is to pull the wool over the eyes of the consumers with flashy science and seemingly impressive statistics in order to make a quick buck, irrespective of the validity and scientific-proof of their products and theories. Because we were all born with a different set of genetics, which contribute to our risk of certain diseases and various other medical conditions, it only makes sense that we eat foods which work well with our blood type in order to combat these potential risks and to promote optimal health.

Well, this is the theory anyway according to Dr. D’Adamo. Dr. D’Adamo has categorised food types which he believes work well with each specific blood type and he recommends that you stick to only consuming foods within the list which corresponds with your blood type, or you may experience a variety of health issues ranging from inflammation and bloating to damaged metabolic function and even cancer.

The central theory to the blood type diet.

Dr. D’Adamo’s central theory as to why he believes the blood type diet is so effective is because it identifies protein lectins which may have a negative effect on individuals with different blood types, and then avoids these specific lectins by eliminating them as a food source.

Lectins are a diverse culture of proteins that can bind sugar molecules. They are considered to be antinutrients and according to Dr. D’Adamo, consumption of the wrong kinds of lectins can lead to agglutination, or the clumping together, of red blood cells. These clumped cells then create a magnetic-like effect on the cells near where they settle (usually in the gut or on other organs). The body then recognises these clumped cells as foreign invaders and eradicates them. These clumped cells can also cause irritable bowel syndrome, cirrhosis in the liver and block blood flow to the kidneys among many other potential health issues.

Lectins are also able to latch onto hormone receptors an either block the ability for hormones to bind to a receptor (works as an antagonist) or it can rev up the hormone receptor non-stop (works as an agonist). Whichever way it affects the cell, it disrupts normal hormone function.

So, if you know your blood type, what should you be eating?

“Old” or Ancient Times

  • These people are intolerant to dietary and environmental adaptations.
  • They should consume lots of lean meats, poultry, and fish.
  • They should restrict grains and legumes.
  • These individuals respond best to stress with vigorous exercise.
  • O blood types require an efficient metabolism to stay lean and energetic.


  • These individuals tend to have a sensitive digestive tract.
  • They work best with a vegetarian diet.
  • Blood types have a tolerant immune system.
  • They adapt well to settled dietary and environmental
  • They typically respond best to stress with calming actions and gentle exercise.
  • Requires an agrarian (based on agriculture) diet to stay lean and productive.

AB Modern

  • They typically have a sensitive digestive tract.
  • AB blood types should avoid chicken, beef and pork.
  • They should eat seafood, dairy and most produce.
  • They respond best to stress spiritually, with physical verve and creative energy.


  • B blood types have a tolerant digestive system.
  • They can tolerate the most flexible dietary choices.
  • These individuals should consume low-fat dairy, meat and produce.
  • They should avoid wheat, corn, and lentils.
  • They respond best to stress with creativity.
  • Should perform moderate exercise.
  • B blood types require a balance between physical and mental activity to stay lean and sharp.

Common concerns

01 Scientific Justification

As mentioned, the health and fitness industry is often plagued with individuals and companies advertising seemingly magic products or fad diets which promise almost overnight results, but unfortunately, this is never really the case. While research has proven that individuals with certain blood types can be predisposed to certain diseases, there is no evidence to suggest that this has anything to do with diet. According to an observational meta-analysis of 1455 young adults who consumed a “type A” diet tested with improved health markers; however, it was everyone who benefitted from this diet and not just those individuals with type A blood.

In a 2013 review of over 1000 studies, researchers were unable to find a single well-designed study which could corroborate the proposed effects of the blood type diet. In fact, the researchers concluded, “No evidence currently exists to validate the purported health benefits of blood type diets.”

02 The Blood Type Diet is Proportioned According to Ethnicity

There is absolutely no scientific reason for the proportionality of food portions according to ethnicity, yet the blood type diet measures this as a factor for nutrient and caloric consumption.

03 The Diet Does Is Not Individualised

While the blood type diet does take a number of factors, with blood type as its central focus, into consideration when dishing out dietary recommendations, it does neglect to take important and scientifically-merited criteria into account.

These include:

  • Current Body Weight
  • Goal Weight
  • Calorie Requirements
  • Activity Level
  • Diet History
  • Food Likes And Dislikes
  • Food Allergies And Intolerances

04 Lectins React with All ABO Blood Types

The central focus to the effectiveness of the blood type diet revolves around a type of protein called lectins and their role in agglutination, however, according to research it appears that the majority of agglutinating lectins react with all ABO blood types.

The one exception being a small percentage of lectins found in raw, uncooked legumes that can have agglutinating activity specific to certain blood groups. With that being said, these exceptions may not even have real-world relevance as their agglutinating effects are only evident when they are consumed raw. The majority of legumes consumed worldwide are typically soaked and/or cooked prior to consumption, rendering the harmful lectins null en void.

More Fad Than Fact

With all the evidence, or lack thereof, taken into account, it is definitely safe to say that Dr. D’Adamo’s blood type diet is more fad than fact. The one redeeming quality of the diet is that it contains mainly healthy, natural whole foods which are a dramatic change to the typical modern diet of processed junk food. Irrespective of blood type, shifting from a junk food diet to a healthy diet which contains these healthy foods is sure to lead to improved health markers and potential weight loss. When it comes to the nutritional split proposed by Dr. D’Adamo, you will most probably find that one, or possibly even two, fits your current way of eating. Perhaps you eat more meat like those in a type O group or perhaps you prefer more plants with little meat like those in the type A group. If you have found that you are getting great results from this style of eating, perhaps you have just found a diet that is appropriate for your metabolism. Chances are that this has nothing to do with your blood type.

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