Researchers have learned that individuals with type A blood have a 14% increased risk of coronary artery disease, whereas those with type O blood have a 15% reduced risk compared to other blood type groups.

There is also some evidence to suggest that those with type A blood have higher total cholesterol and LDL cholesterol, and type O folks have an increased risk of type 2 diabetes compared with type B blood group.

Based on this information, do people in different blood groups benefit from different diets? Should you eat for your blood type?

Dr. Peter J. D’Adamo certainly thinks so. In his popular book Eat Right 4 Your Type published in 1996, he recommends that blood type A individuals eat a meat-free diet of fruits, vegetables, legumes and whole grains, and type O individuals eat a more meat-centric diet. He theorized that if we eat according to our blood type, we can improve our health and decrease the risk of chronic disease.

Since then, numerous papers have been published debunking the blood type dietary theory. And now there is an intervention trial published August 2020 in the Journal of the Academy of Nutrition and Dietetics that proves his advice is not supported by science.

Low-Fat Plant-Based Diet Put to the Test

In this 16-week randomized clinical trial, the intervention group participants were all placed on a low-fat vegan diet similar to the diet Dr. D’Adamo recommended for individuals with type A blood, and recommended against those with type O blood. The control group made no dietary changes.

Participants’ body weight, BMI, fat mass, visceral adipose tissue volume, blood lipid levels, fasting glucose, and HbA1c were recorded at the beginning and at the end of the trial.

How did it turn out?

There was no significant difference between the blood type groups.

  • They all lost weight, from 12.5 – 15.6 pounds
  • Their BMI went down by 2.1 – 2.5 points
  • Their fat mass was reduced by 3.9 – 5.0 grams
  • Their fasting glucose improved by 1.6 to 4.4 mg/dL
  • Their total cholesterol dropped 17.2 – 18.4 mg/dL
  • Their LDL cholesterol dropped 11 – 13.6 mg/dL

Here is the a detailed slide showing all of the outcomes:

(c) Copyright Journal of the Academy of Nutrition and Dietetics,

Researchers concluded:

“Dietary changes, especially increased intake of fruits, vegetables, and grains, are beneficial not only to individual with blood type A, but also to all individuals regardless of blood type, and that there is no apparent value of limiting these healthful diet changes to a specific set of individuals based on ABO blood group.”

So, who is a low-fat plant-based diet good for?

Every blood type.

I still see copies of Eat Right 4 Your Type laying around on people’s tables and on their bookshelves. It was translated into at least 52 languages and sold over 7 million copies. (So much bad information out there!)

It underscores the importance of selecting a diet based on the abundance of research now available on how best to eat for overall health, rather than popularity or a book author’s credentials.

The research overwhelming points to a whole food, plant-based diet as the best diet for preventing, managing and even reversing chronic conditions like heart disease, high blood pressure and type 2 diabetes.

If you’d like to make the transition to this way of eating, check out the Juicy Plant-Based KickStart Program where I support clients 1-on-1 in a 6-week program designed to help them harness the power of plants for better health.

You might also be interested in watching the video What is a Whole Food, Plant-Based Diet?