Go to page content

What Is The Blood Type Diet?

Is the blood type diet right for you? Learn the facts here so you can make an informed decision.

A young woman adapting a blood type diet with a healthy meal consisting of salmon and tomatoes

Have you ever heard of the blood type diet? This diet was the subject of the best-selling book “Eat Right 4 Your Type” by Dr. Peter J D’Adamo.

In the book, D’Adamo explains how he thinks your blood type affects your body chemistry and determines what foods you should be eating. D’Adamo said that his patients who went on this diet reported increased weight loss, better digestive function, more energy, and improved mental clarity.

But are any of these findings substantiated by science? So far, no major studies have been able to pinpoint any evidence that the blood type diet can help with any of the issues D’Adamo claims it addresses. In fact, the diet has been debunked by a study that says everyone — not just people with certain blood types — benefits from a plant-based diet.

So, why does the popularity of the blood type diet persist? Is there anything we can learn from it? Keep reading to learn more about this controversial way of eating.

What Is The Blood Type Diet? 

The blood type diet is based on the evolution of the four blood types: A, AB, B, and O. Genetic markers tell us when each blood type arose, and what ancient people with those blood types ate. For example, the first ancient people with blood type A were farmers and, therefore, evolved to eat the grains they grew.

In “Eat Right 4 Your Type,” D’Adamo says that you may be more susceptible to different health conditions based on your blood type. For example, he claims that people with O blood type are more prone to allergies and hay fever.

There is no scientific evidence to back up these claims, but that doesn’t mean that all of the advice in the book is unhelpful. D’Adamo recommends that people of all blood types eat more whole foods and cut out processed foods.

Most experts agree that this sensible, science-based nutritional advice is the key to good health. Traditional Chinese Medicine (TCM) Physician Lim Sock Ling agrees. Physician Lim stresses the importance of eating well because “blood originates from food essence, which is derived from digested food.”

She describes the main functions of blood:

  • To provide nutrients for organs, tissues and meridians
  • To nourish the skin, bones, and muscles
  • Maintain healthy body movement and sensation

A poor diet can result in symptoms like dizziness, vertigo, ringing in the ears (tinnitus), or limb weakness. It can also result in slower thinking, memory issues, and insomnia.

Type A

A woman with red curly hair arranging a plate of cooked vegetarian salad for dinner
According to the blood type diet, a vegetarian diet is best for people with blood type A.

People with blood type A are descended from ancient people who were farmers. D’Adamo says type As can digest carbohydrates better than other blood types and do well on a meat-free diet. For best health, he suggests you eat a diet rich in fresh fruits and vegetables, beans and legumes, and whole grains. D’Adamo says people with type A blood have a sensitive immune system and should choose organic foods when possible.

Type AB

People with blood type AB can enjoy a wider variety of foods for both types A and B, according to D’Adamo. Tofu, seafood, dairy, and green vegetables are all recommended. Foods to avoid include red meat, beans, corn, and smoked or cured meats.

Type B

People with type B blood are thought to have descended from nomads and therefore equipped to eat a variety of foods, according to D’Adamo’s analysis. He suggests you eat a diet full of fresh fruits, vegetables, and meats. The main foods to avoid are corn, wheat, buckwheat, lentils, tomatoes, peanuts and sesame seeds, and chicken.

Type O 

A man eating cooked well done steak with mustard sauce for lunch
Red meat is a recommended dietary choice for people with blood type O.

Type O is the first known blood type, and people with it have ancestral ties to hunter-gatherers, says Dr. D’Adamo. The O blood type diet is close to the paleo diet, filled with lean meats, poultry, fish, and vegetables. Avoid high-carbohydrate foods like grains, beans, and corn. You can eat dairy in moderation.

Why The Blood Type Diet Is Thought To Work  

Why do we have different blood types? And why would blood type have an impact on how food affects us? Blood types are thought to be related to our immune system and help ward off diseases. By eating foods we are genetically equipped to eat, we can avoid inflammation that is thought to be the cause of many diseases. The diet claims to offer an easy way to identify the foods that are best for your unique biochemical makeup.

What do lectins have to do with it?

According to the blood type diet, eating food that contain lectins could lead to the clumping together of red blood cells.

Lectins are a type of protein found in certain foods, such as beans, grains, and legumes, that bind to the lining of the digestive tract and prevent the absorption of certain minerals. They are known as anti-nutrients.

The blood type diet states that lectins target ABO blood types. So, is there any truth to this? Research shows that lectins in raw, uncooked legumes may cause clumping in certain blood types. For example, raw lime beans may interact with red blood cells in blood type A individuals.

However, most lectins react with all blood types and therefore are not specific to a certain blood type, with the exception of raw legumes. You can deactivate antinutrients, such as lectin, by soaking your beans, grains, and legumes in water before cooking.

Does The Blood Type Diet Really Work?

Most experts do not recommend this diet. That doesn’t mean that there is nothing we can learn from the blood type diet. One major takeaway is that there is no one-size-fits-all way to eat.

This isn’t a new way of thinking. This individualized way of thinking about health is basic to TCM. In TCM, practitioners evaluate their patients in a holistic manner and treat the body as a whole. While TCM and the blood type diet aren’t the same, their approach to eating is very similar. Physician Lim recommends a specifically-tailored diet for each of her patients. She uses a patient’s current body constitution, lifestyle, and external factors to help her determine that regimen.

If you’re still curious about the blood type diet, here are some pros and cons to help you decide if it’s right for you.


The general advice the diet offers for most people — eating more whole foods and more leafy greens and reducing consumption of processed foods — is universally healthy.

Nutritious whole foods arranged in a flat lay on top of a kitchen counter.
The blood type diet recommends eating more whole foods, vegetables, and fruits.


The various “type” diets are too restrictive. Not only is a restrictive diet difficult to maintain, but you may also become deficient in certain vitamins and minerals because of the limited number of foods you can eat. If you need help with weight loss, digestion, or energy, adding a supplement to your diet may be more effective.

Whether or not you want to try the blood type diet is up to you. Just keep in mind that no scientific studies have found that determining what you should eat based on your blood type is effective.

Fad diets will come and go, but a balanced diet filled with whole foods and lots of fresh fruits and vegetables will always be medically sound. It may also be beneficial to take an immune-boosting supplement to further protect against diseases.

Share this article with your friends and family who struggle with finding the right diet. 


  1. Harvard Health Blog. 2019. Diet not working? Maybe it’s not your type.
  2. American Red Cross. N.d. Facts About Blood and Blood Types.
  3. Eat Right 4 Your Type. 2019. Blood Type and Your Health.
  4. Physicians Committee For Responsible Medicine. 2020. New Study Debunks Blood Type Diet.
  5. T. Colin Campbell Center For Nutrition Studies. 2019. The Blood Type Diet: Science or Fiction?
  6. NCBI. 2013. Blood type diets lack supporting evidence: a systematic review. 
  7. Glycobiology. 2014. History of lectins: from hemagglutinins to biological recognition molecules.

Share this article on

Was This Article Useful to You?

Want more healthy tips?

Get All Things Health in your mailbox today!

Subscribe to our newsletter

Related Articles

Monosodium glutamate MSG min scaled
Weight & Fitness

Should You Avoid Monosodium Glutamate (MSG)?

Have you heard about the negative health effects of monosodium glutamate (MSG)? Find out if they're true here - and what you can use to replace MSG with if you still have concerns.

Read More
The health benefits of lemon water
Weight & Fitness

The Benefits of Lemon Water 

Lemon water is often touted as an ultra-healthy drink that can result in a host of health benefits, such as improved digestion, detoxification and improved complexion.

Read More
Dos and donts detox diet min scaled
Weight & Fitness

Do's And Don'ts When You Go On A Detox Diet

A detox diet doesn't have to be a diet at all. Incorporate these tips into your daily routine and you'll naturally support the organs that purge toxins.

Read More
Refusing salt min scaled
Weight & Fitness

Tips To Help Reduce Your Intake Of Salty Foods

Do you crave salty foods? Giving in to those temptations every once and awhile doesn't hurt, but regular consumption can increase your risk of heart complications. These tips can help you bring down your dietary salt intake.

Read More
A woman measuring her slim waist in the kitchen
Weight & Fitness

The 8 Best Foods for Weight Loss

Looking to loss weight this year? While a workout plan and a balanced diet is essential, it's also important to eat delicious superfoods to benefit your overall health and wellbeing.

Read More

The contents of the All Things Health website are for informational and educational purposes only.
Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment.