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Blood Type Diet: What It Is, What Foods To Eat And How It Works

Blood Type Diet: What It Is, What Foods To Eat And How It Works
Liam Agnew
Sport and Performance Nutritionist3 years ago
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The Blood Type Diet has gained some popularity in the last couple of decades. It focuses on less of a ‘one size fits all’ approach that other diets like the vegan, carnivore or Mediterranean diet; it focuses on what you should eat based on your blood type. Whilst this sounds like a particular technical way to approach your diet, there’s no scientific evidence to support the claims. So is any of it useful? Let’s delve into what the diet entails to find out.Jump to:


What Is the Blood Type Diet?

The Blood Type Diet or the Blood Group Diet is a fad diet that focuses on eating (or avoiding) certain foods based on your blood type - A, B, AB or O. Popularised by Dr Peter D’Adamo’s book, Eat Right 4 Your Type, it claims that you can optimise your health through individualisation of your diet, depending on your blood type. 

The idea requires you to look at the genetic traits of your ancestors, finding where they were from and subsequently what they ate. D’Adamo claims that following the diet will allow you to digest your food better, improve energy levels, lose weight and even reduce the risk of certain diseases. However, there’s no scientific evidence to support these claims.1


What To Eat for Your Blood Group

The 4 main blood groups, A, B, AB and O. each have positive and negative sub groups. The Blood Type Diet recommends which foods you should choose based on your blood group.  


Blood Group A:

Described by D’Amado as "cultivators"1, individuals with this blood group are advised to follow a dairy free diet, vegetarian diet high in vegetables, fruits, grains, beans, legumes, nuts and seeds. 

D’Adamo claims those with blood group A have a sensitive immune system and should therefore choose organic, fresh whole grains.1 Again, these are unsubstantiated claims, and whilst eating plenty of fresh veg and whole grains is good for you, you may also need dairy and meat for things like calcium and protein.


Blood Group B:

These people are referred to as ‘’the nomad’’1 and should be eating certain meats, green vegetables, eggs and low-fat dairy. Nuts, seeds, corn, wheat, lentils, tomatoes and chicken should be avoided. 

However, all of these foods on the “avoid” list have tonnes of health benefits. Nuts for example are a great source of healthy fat, and lentils have a brilliant fibre content. 


Blood Group AB:

Described by D’Adamo as an "enigma"1 this blood group can eat any food from group A or B but are advised to follow a predominately vegan diet. There are no specific foods which they need to avoid, although D’Amado claims that these people tend to have low stomach acid, so caffeine and alcohol should be avoided. 

Again, these claims aren’t backed up by scientific evidence, and a vegan diet may not be the right choice for many people. 


Blood Group O:

This group is called "the hunter"1 and it’s recommended they eat a grain and dairy free diet which is high in lean meat, fish and poultry with a moderate number of vegetables, eggs, nuts, and seeds. 

Any diet recommending a “moderate” intake of vegetables is a little bit questionable. Including a big variety of fruits and vegetables is recommended for a healthy lifestyle, unless you’ve been advised otherwise by your doctor. 

Does The Blood Type Diet Work?

There is currently no scientific evidence to support the theory that the right diet for you is dependent upon your blood type. In fact, a study performed in 2014 that included 1,455 participants showed no data to support the hypothesis.2 However, that doesn’t mean that diet can’t work. 

The critical part of whether a diet will be successful is whether or not it ensures you get all of the micro and macronutrients you need, and gives you the right number of calories, whether that be a deficit or a surplus.

The blood type diet does encourage healthy, unprocessed foods which are definitely good for you and will help if you’re looking to lose weight. Although, some of the blood groups have pretty restrictive suggestions, so will struggle to give you everything you need. Specifically for O and A, the diet is somewhat restrictive and may result in deficiency in certain vitamins and minerals.

If you find you can enjoy eating these foods and you are able to stick to it for months at a time, it may well work for you. Any weight loss results that occur whilst following the blood type diet will be due to a calorie restriction and there are lots of other less restrictive ways to do this.


Take Home Message

The blood type diet is based on eating foods aligned to your blood type proposed to help lose weight, improve digestion and increase energy levels. These claims are based on theory alone with no scientific evidence to support them. 

However, the diet does generally promote healthy food choices (with some blood groups more restrictive than others), so it may be worth trying out for a healthy lifestyle. Just bear in mind that there are other, less restrictive ways to get healthier and/or lose some weight.
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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

  1. Cusack L, De Buck E, Compernolle V, Vandekerckhove P. Blood type diets lack supporting evidence: A systematic reviewAm J Clin Nutr. 2013;98(1):99-104. doi:10.3945/ajcn.113.058693 
  2. Wang J, García-Bailo B, Nielsen DE, El-Sohemy A (2014) ABO Genotype, ‘Blood-Type’ Diet and Cardiometabolic Risk Factors. PLoS ONE 9(1): e84749. 
Liam Agnew
Sport and Performance Nutritionist
View Liam Agnew's profile

Liam is a certified sport nutritionist with the International Society of Sport Nutrition and is enrolled on the British Dietetics Association’s Sport and Exercise Nutrition register. He has a Bachelor’s of Science in Sport and Exercise Science and is graduate of the ISSN Diploma in Applied Sport and Exercise Nutrition.

Liam is an experienced personal trainer, helping clients reach their health and fitness goals with practical, evidence informed exercise and nutrition advice. In his spare time Liam has competed in numerous powerlifting competitions and enjoys hill walking, football and expanding his recipe repertoire in the kitchen.

Find out more about Liam's experience here.