The Blood Type Diet

How Does the Blood Type Diet Work?

The following explanation of how the Blood Type Diet works is based on the description written by its creator. Everyone responds differently to nutrition plans, and you should always talk to your doctor before starting any new diet. These claims are not backed by WebMD.

You're born with a certain blood type depending on the blood types of your biological parents. The four major blood groups are categorized based on two antigens, A and B, either being present or absent on the surface of your red blood cells. For example, someone with both antigens has AB blood, but someone with neither antigen present has O blood.

D'Adamo claims that the antigens found in your blood that decide whether you’re type O, A, B, or AB, are also present in other parts of your body, including your digestive tract. That’s what causes the foods you eat to react chemically with your blood type, he says.

People with different blood types also have different gut bacteria, which D’Adamo traces back to our early ancestors. His research suggests that the first humans had type O blood. Since they were hunter-gatherers, they ate fewer carbs and more protein. Those with A blood types are believed to have descended from farmers, which is why D’Adamo urges a diet with more vegetables for this group. He thinks B blood types can digest more fat because they supposedly evolved from nomadic tribes, whose diets were rich in meat and dairy.

D'Adamo claims if you eat foods that were common when your blood type evolved, your body will digest food more efficiently.

How Do I Start the Blood Type Diet?

The first thing you need to know before starting this diet is your blood type. Take a blood test to find out your blood type if you don't already know it. You can request a test from your doctor, or you might be able to get your blood type confirmed while donating blood at a blood drive.

It’s worth noting that each person has an Rh, or Rhesus, factor in their red blood cells. Your blood will either be positive (+) if you have the Rh factor present, or negative (-) if you don’t. For the Blood Type Diet, your blood being positive or negative doesn’t play as big a role as the blood type group.

Once you know whether you’re type O, A, B, or AB, you can plan your snacks and meals around which foods are best for you. It’s possible for you to start this diet right away, or by slowly replacing the foods in your kitchen with ones that are better suited to your blood type.

Blood Type Diet Foods

What you’ll eat on this diet depends on your blood type. Here's what D'Adamo suggests for each group:

O blood type diet

It's a high-protein diet that's heavy on lean meat, poultry, fish, fruits, and vegetables, and light on grains, beans, and dairy. If your goal is to lose weight, you should avoid carbs and choose seafood, kelp, red meat, broccoli, spinach, and olive oil. D'Adamo also recommends various supplements to help with tummy troubles and other issues he says people with type O tend to have.

A blood type diet

This involves a vegetarian diet based on fruits and vegetables, tofu, beans and legumes, and whole grains -- ideally, organic and fresh -- because D'Adamo says people with type A blood have a sensitive immune system.

Vegetables, pineapple, olive oil, and soy are best for weight loss, but dairy, wheat, corn, and kidney beans may lead to weight gain, he adds.

B blood type diet

It's a mixed diet that includes meat, fruit, dairy, seafood, and grains. Avoid corn, wheat, buckwheat, lentils, tomatoes, peanuts, and sesame seeds. Chicken is also problematic, D'Adamo says. He encourages eating green vegetables, eggs, certain meats, and low-fat dairy.

AB blood type diet

Foods to focus on include tofu, seafood, dairy, and green vegetables. D'Adamo says people with type AB blood tend to have low stomach acid and should avoid caffeine, alcohol, and smoked or cured meats. Some dairy, such as yogurt and kefir, are also good for this group.

Pros and Cons of the Blood Type Diet

Every diet has its pros and cons. Depending on your lifestyle and food preferences, some diets may suit you more than others.

Benefits of the Blood Type Diet

According to D'Adamo, proteins in certain foods called lectins can bind to your blood type antigen and make your blood stick together. This results in fatigue, headaches, digestive issues, and skin problems, he says. Eating foods that your body responds well to may improve things such as digestion, energy levels, and some chronic conditions, such as heartburn.

D’Adamo also claims that each blood type is at higher risk for some diseases. People with type O blood, for example, may be more likely to get stomach ulcers, while heart disease and diabetes are more common in people with type A blood. He says you may be able to lower your chances of getting some diseases by choosing a diet that is most compatible with your blood type.

Risks of the Blood Type Diet

There’s no scientific evidence to support the benefits of the Blood Type Diet. In 2013, researchers reviewed all of the existing medical literature on the subject (1,415 references in total) and found no studies showing that the Blood Type Diet works. D’Adamo’s idea about ancestral blood types has also been questioned. Other researchers suggest that type AB may have actually been the first ever blood group, not O.

Another study published in 2021 examined if people with heart disease could benefit from a plant-based diet depending on their blood type. No connection was found between blood types and their health outcomes, however.

It’s worth noting that most of the foods suggested for the Blood Type Diet are healthy, but if you try the Type B diet, you should watch your red meat and dairy intake. Since these foods are higher in saturated fat, having too much of either may raise your chances of getting heart disease.

Does it allow for restrictions or preferences?

Because the diet dictates that you eat very specific types of food based on your blood type, it doesn't allow much for personal tastes. For example, if you're a big fan of meat, you won't be very happy on the type A diet, which is mostly vegetarian. If you’re lactose intolerant, you may have a hard time with the B blood type diet, which recommends dairy. There are even suggestions about the types of spices and condiments you can use.

If you're looking for a diet that's gluten-free, you should know that this diet doesn't ban gluten. You may be able to make gluten-free choices if you read food labels carefully.

Level of effort: high 

Since the list of approved and restricted foods for each blood type is long, you may need to severely restrict what you eat. Your blood type will determine your shopping list and your choices when eating out. If you live with people who have different blood types, meal planning may be hard. Packaged foods and in-person meetings, however, are not required for this diet.

What else you should know

Cost. D'Adamo recommends a lot of specialty and organic foods (such as soy milk and carob chip cookies), which can be pricey. Vitamins and herbal supplements are also part of the diet.

Support. Beyond D'Adamo's book and website, you do this diet on your own.

Exercise. The Blood Type Diet recommends exercises based on your blood type. For instance, it suggests yoga or tai chi for blood type A, and vigorous aerobic exercises such as jogging or biking for up to an hour a day for type O. Type B, he says, should focus on group exercises, such as tennis, martial arts, or golf, while a mix of calming and aerobic exercise is best for AB types. 

Blood Type Diet Review: What Our Expert Says

Does the Blood Type Diet work?

Though the Blood Type Diet has been around for a while, Kathleen Zelman, MPH, RDN, LD, a registered dietitian nutritionist, explains that the theory behind the diet has been debunked. “It's somewhat of a gimmicky way to try to get people to eat healthier. There is absolutely no science to substantiate that your blood type dictates the kind of diet that you should be on,” she says.

Zelman notes that elements of the Blood Type Diet do work since it’s mostly a healthy, plant-forward diet. She cites a 2014 study that found adults eating the type A diet showed improved health markers, but this occurred in everyone, not just those with type A blood type.

The diet recommends high-quality food, lots of fruits and vegetables, fiber, vitamins and minerals, lean meats, and foods low in saturated fat. And, by cutting calories and eliminating added sugar, you’re likely to lose weight.

Still, if you follow the guidelines for just your blood type, it may not be the most effective option for you.

Is the Blood Type Diet good for certain conditions?

“The best diet is the one that you can stick with, and the best diet is the one that's customized for you,” Zelman says. “And I wouldn't call blood typing customized because it doesn't really address other conditions.”

Depending on your blood type, the diet outlined may not support treatment for cardiovascular disease, high blood pressure, or high cholesterol levels. For example, the type B diet has more saturated fat than the other types, which can put you at risk for heart disease. The fruits and vegetables emphasized in other parts of the diet plan are lower in saturated fat, however.

“If you have heart disease, if you have diabetes, this diet could probably be modified, without eliminating some of the foods [D’Adamo] does, to improve your health. But it has nothing to do with your blood type,” she says.

Zelman recommends that you check with your doctor or see a registered dietitian nutritionist before starting a diet such as the Blood Type Diet.

Are there concerns about the recommended food guidelines in the Blood Type Diet?

Zelman doesn’t find the foods listed for blood types O, A, B, and AB concerning, but she does see issues with what people are told to stop eating. For example, she says, “There's really no sense in getting rid of eggplant.”

Due to D’Adamo’s theory on lectins in certain foods causing health issues, the diet many grocery list items are removed from the diet.

“Foods like beans and whole grains that contain lectins -- they have good-for-you nutrients, and they shouldn't be eliminated,” Zelman says.

She also explains that while reducing the intake of processed foods can be beneficial, not all processed foods are bad. Milk and wheat, for example, need processing for safety reasons and to make them more digestible.

Finally, Zelman notes that it’s OK if you can’t always buy the organic versions of food recommended by this diet, which can be expensive. “It’s much more important to eat more fruits and vegetables than to worry about whether they're organic or not,” she says.

Can kids try the Blood Type Diet?

If families try the Blood Type Diet, it might be challenging to meet everyone’s needs, especially if you follow it strictly. Zelman gives the example of avoiding dairy (part of the type O and A diets), which could be harmful to children.

“Dairy is so critically important to growth and development for kids to get enough calcium and vitamin D,” she says.

The general idea of the diet -- fewer processed foods, less added sugars, eating lean meats and lots of fruits and vegetables -- are all good for everyone’s overall health, Zelman says. Once you start customizing the diet for your family, it’s not really the Blood Type Diet anymore, though.

“There's no problem in modifying this diet to meet your family’s needs. But when I say modifying it, you're essentially then following a healthy meal plan that's advocated by the American Heart Association, and by the Dietary Guidelines,” she says.

Blood Type Diet Recipes

The following recipes, organized by blood type, are based on D'Adamo's Blood Type Diet:

Recipes for type O blood

Breakfast: Mucho mango smoothie

Ingredients:

• 8 ounces pineapple juice (best if fresh or made from frozen concentrate)
• 1 mango, peeled, pitted and chopped
• 1 medium banana
• 7-8 ice cubes
• 1/3 cup frozen blueberries (optional)

Instructions:

1. Add all ingredients to a blender or food processor and blend until smooth.
2. Serve immediately or freeze to make popsicles.

Lunch: Black bean soup with meat

Ingredients:

• 1 tablespoon olive oil
• 2 onions, chopped
• 10 cloves of garlic, minced
• 1 pound grass-fed ground beef
• 1 package roasted red pepper sausage
• 3 teaspoons chili powder
• 2 teaspoons cumin
• 5 cups beef broth
• 2 cans (15 ounces) of black beans or 4 cups of prepared black beans
• 1/2 cup wakame 
• 3 cups basmati rice, precooked
• Sea salt/fresh ground green peppercorns to taste

Instructions: 

1. In a large frying pan, heat oil over medium heat. Brown onions, garlic, and sausage.
2. In a separate pan, brown ground beef, then drain and add to the onion mixture.
3. Continue cooking, and add chili powder, cumin, beef broth, Wakame, and one can of beans.
4. In a food processor or blender, puree the remaining can of beans and add to the pan.
5. Reduce heat, cover it, and simmer for 15-20 minutes on medium.
6. Add rice, reduce heat to low, and simmer for another 30 minutes.

Dinner: Simple sesame chicken

Ingredients:

• 4 chicken breasts (bone-in)
• 2 tablespoons soy or tamari sauce
• 3-4 cloves garlic, crushed and peeled
• 1/4 cup sesame seeds

Instructions:

1. Preheat the oven to 375 F.
2. Put chicken pieces in a baking dish.
3. Add soy sauce to the dish. Rub the chicken with crushed garlic, salt, and pepper.
4. Sprinkle sesame seeds over top and bake for 50 minutes, or until done.
5. Serve with rice or spelt noodles and a salad.

Recipes for type A blood

Breakfast: Silken tofu scramble

Ingredients:

• 1 tablespoon olive oil
• 1 teaspoon minced garlic
• 1 small carrot, grated
• 1 small zucchini, grated
• 5 ounces silken tofu
• Pinch of salt
• 1 tablespoon chopped fresh parsley or basil

Instructions:

1. In a small skillet, heat oil over low heat.
2. Add garlic and saute for 2 minutes.
3. Add carrot and cook for an additional 3-4 minutes.
4. Add zucchini and tofu.
5. Break up the tofu with the side of a spoon. Stir the mixture until cooked.
6. Season with salt and herbs.

Lunch: Lentil soup

Ingredients:

• 1 package of dried lentils
• 1 carrot, chopped
• 1 celery stalk, chopped
• 2-3 portobello mushrooms, chopped
• 1/2 onion, chopped
• 1 teaspoon marjoram
• 2 vegetable bouillon cubes
• 1 tablespoon sea salt
• 6 cups water
• 8 ounces tomato sauce (optional)

Instructions:

1. Saute onion in a large pot. Add the rest of the chopped vegetables and cook until slightly tender.
2. Dissolve bouillon in water and add to the pot, along with the tomato sauce. Bring the mixture to a boil.
3. Add the lentils and simmer on low for 1 hour.
4. Add salt and marjoram to taste.

Dinner: Spinach feta rice

Ingredients:

• 1 cup uncooked long-grain rice
• 1 cup fat-free chicken broth
• 1 cup water
• 1 medium onion, chopped
• 1 cup sliced portobello mushrooms (approximately 4 large)
• 2 cloves garlic, minced
• 1 tablespoon lemon juice
• 1/2 teaspoon salt
• 1/2 teaspoon dried oregano leaves, crushed
• 1 package chopped frozen spinach, cooked and drained according to directions, or 6 cups shredded fresh spinach leaves
• 4 ounces feta cheese, crumbled

Instructions:

1. Combine broth and water in a medium saucepan.
2. Bring mixture to boil.
3. Add rice, stirring only once.
4. Reduce heat to low.
5. Cover and let simmer for 15-20 minutes or until rice is tender and the liquid has been absorbed.
6. In another pan, cook the onion, mushrooms, and garlic until tender.
7. Add cooked spinach, oregano leaves, salt, and lemon juice.
8. Add the entire mixture to rice (or vice versa). Finish by adding feta cheese. 

Recipes for type B blood

Breakfast: Breakfast “cake”

Ingredients:

• 4 eggs
• 1 cup of applesauce or fruit puree
• 1 1/3 cups of quinoa flakes
• 1 1/2 cups frozen blueberries
• 40 almonds, crushed
• 2 tablespoons flaxseeds
• 4 tablespoons chia seeds
• 1 teaspoon baking soda
• 2 teaspoons lemon juice
• Cinnamon, ginger, and allspice to taste
• Pinch of sea salt

Instructions:

1. Preheat the oven to 325 F.
2. Beat 4 eggs with a whisk, then add the chia seeds and applesauce.
3. Let sit until the chia seeds expand a bit.
4. Add lemon juice and whisk again.
5. In a separate bowl, combine quinoa flakes, baking soda, sea salt, and spices.
6. Fold dry ingredients into the wet mixture, then add frozen blueberries and mix again.
7. Grease an 8 x 4 loaf pan and bake for 40 minutes, or until firm to the touch.

Lunch: Egg and seaweed soup

Ingredients:

• 2 cups turkey stock
• 2 cups water
• 1/2 cup sliced vegetable of choice (celery, carrots, mushrooms, etc.)
• 2 teaspoons arrowroot
• 2 sheets of dried Nori
• 1 egg
• A dash of sea salt
• 3 sprigs of green onion
• 2 teaspoons ume plum vinegar (or soy sauce)
• 1/4 teaspoon white pepper (optional)
• 1/4 teaspoon (or more) ground red pepper flakes (optional)
• 1/4 teaspoon marmite (optional)

Instructions:

1. Boil the water and stock together in a pot.
2. Add the vegetables and boil until tender.
3. To thicken the soup, mix 1 teaspoon of arrowroot with some water and pour it into boiling water.
4. Break the nori into small pieces and add them to the soup mixture.
5. Mix the remaining teaspoon of arrowroot with water, add one egg, and beat.
6. Turn off the heat. When the mixture stops boiling, slowly pour the egg mixture into the soup. Let it sit for 1 minute, then bring to a gentle boil and gently stir to distribute eggs.
7. Add salt and spices, marmite, and vinegar to taste. Serve with sliced green onions.

Dinner: Lamb chops with yogurt sauce

Ingredients: 

• 1 rack of lamb, cut into single-bone servings
• Rosemary, minced
• Crushed garlic to taste
• Olive oil
• 1/3 cup chopped mint
• 2 tablespoons chopped basil
• 1 cup plain yogurt
• 1/4 teaspoon ground cardamom
• 1 tablespoon honey
• Salt and pepper to taste

Instructions:

1. Season the meat with salt, pepper, rosemary, and crushed garlic.
2. Rub meat with olive oil, then quickly flame-grill it over a very hot grill, taking the chops off when the meat is still rare but charred on the outside.
3. To make the yogurt sauce, mix yogurt, mint, basil, cardamom, honey, and salt and pepper to taste.
4. Serve chops with a dollop of sauce.

Recipes for type AB blood

Breakfast: Egg and banana pancakes

Ingredients:

• 1-2 eggs
• 1 banana (ripe)
• 1 dash of cinnamon
• Ghee
• Agave syrup (optional)
• Blueberries (optional)

Instructions:

1. Mash a ripe banana, and add to it whisked eggs and cinnamon.
2. Melt some ghee in the pan and add 1/4 cup of pancake batter. Cook for about 30 seconds on each side.
3. Serve with blueberries and agave.

Lunch: Soy, ginger and broccoli stir-fry

Ingredients: 

• 1 pound extra firm tofu, cut into 1-inch squares
• 1/2 cup sake or white wine
• 4 tablespoons soy sauce
• 2 tablespoons olive oil
• 2 medium cloves garlic, minced
• 2 tablespoons ginger juice
• 1 onion, thinly sliced
• 2 cups broccoli florets
• 8 ounces snow peas
• 1/4 cup roasted almonds

Instructions:

1. In a large wok, bring soy sauce, garlic, ginger, and sake (wine) to a boil
2. Add tofu cubes. Cover and simmer for 5-10 minutes.
3. Remove the tofu and the remaining broth from the wok.
4. Heat oil in the wok and stir-fry vegetables over medium heat for 3-5 minutes.
5. Add the broth and tofu back to the wok and mix.
6. Serve with roasted almonds.

Dinner: Pumpkin dal

Ingredients:

• 1 tablespoon olive oil
• 2 teaspoons onion powder
• 2 cloves garlic
• 1 tablespoon ginger root, grated
• 1 teaspoon turmeric powder
• 1 teaspoon coriander powder
• 1/4 teaspoon black pepper
• 1/4 teaspoon cayenne pepper
• 8 ounces of red lentils
• 16 ounces of canned pumpkin
• 4 cups vegetable broth
• 1 1/2 teaspoons sea salt

Instructions:

1. Heat oil in a saucepan and add onion powder, garlic and ginger root. Cook for 5 minutes before adding the rest of the spices.
2. Add broth, lentils, salt and pumpkin. Stir until the pumpkin is completely blended with the broth.
3. Cook on medium-low heat for 45-60 minutes, stirring occasionally.

Blood Type Diet FAQs

Is the Blood Type Diet healthy?

While there’s no proof that the Blood Type Diet works, there’s also no proof that it’s harmful. But when it comes to choosing the diet that’s best for you, it’s better to consider whether certain diseases run in your family over your blood type.

How fast can I lose weight on the Blood Type Diet?

D’Adamo says most people on the Blood Type Diet start to see some results in 2 weeks, which can include weight loss.

Can a person with blood type O eat eggs?

Eggs are considered to be a neutral food for all blood types, including type O, according to the Blood Type Diet.

What is the healthiest blood type?

There isn’t one blood type that’s healthier than another. Each one has its own benefits and potential health considerations.