What Is the Blood Type Diet?
The idea behind the Blood Type Diet is that we all have different nutritional needs depending on our blood type — O, A, B, or AB.
In 1996, naturopathic doctor Peter J. D’Adamo wrote a bestselling book called Eat Right 4 Your Type, where he claimed that certain foods can lower inflammation, boost energy, help with weight loss, and prevent disease.
In the years since D’Adamo introduced the Blood Type Diet, many studies have looked into whether the diet actually works, but none of them have shown a clear link between eating according to your blood type and better health.
Still, the diet’s focus on healthy foods has shown benefits for some people. It may be useful for you if you want to try it and your doctor agrees.
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. (Antigens tell your immune system whether or not something is harmful.)
For example, if you have both antigens, you have type AB blood, but if you have neither antigen present, you have type O blood.
Blood type diet to lose weight
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. People 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 that eating foods that were common when your blood type evolved may help your body digest food more easily.
How Do I Start the Blood Type Diet?
The first thing you need to know before starting this eating plan is your blood type. You’ll have to take a 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 on their red blood cells. This is a special protein that you inherit from your parents. When you take a blood test, your blood type 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 supposed to be best for you. You can decide whether to start this diet right away. Or you could take your time and slowly replace 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
This is a high-protein diet that’s heavy on lean meat, poultry, fish, fruits, and vegetables, while light on grains, beans, and dairy. If your goal is to lose weight, you’ll want to avoid carbohydrates. Instead, choose seafood, kelp, red meat, broccoli, spinach, and olive oil. D’Adamo also suggests taking various supplements to help with digestive troubles and other issues he says people with type O blood tend to have.
A blood type diet
Type A blood types are advised to stick to a vegetarian diet full of 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, while dairy, wheat, corn, and kidney beans may lead to weight gain, he adds.
B blood type diet
If you have type B blood, a mixed diet that includes meat, fruit, dairy, seafood, and grains is thought to be best. Foods to avoid include corn, wheat, buckwheat, lentils, tomatoes, peanuts, and sesame seeds. Chicken can also be problematic, D’Adamo says. The list of foods to eat more of includes green vegetables, eggs, certain meats, and low-fat dairy.
AB blood type diet
Foods to focus on for this blood type group include tofu, seafood, dairy, and green vegetables. D’Adamo believes that people with type AB blood tend to have low stomach acid and because of that, should avoid caffeine, alcohol, and smoked or cured meats. Some dairy products, such as yogurt and kefir, are also good for this group.
Pros and Cons of the Blood Type Diet
Every diet, including the Blood Type Diet, has pros and cons. Depending on your lifestyle and food preferences, some ways of eating 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 your digestion, energy levels, and some chronic conditions, such as heartburn.
D’Adamo also claims that each blood type is at a 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 works best 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 studied all of the existing medical literature on the subject (1,415 references in total). They 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.
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. As these foods are higher in saturated fat, having too much of either may raise your chances of heart disease.
Does it allow for restrictions or preferences?
Because the Blood Type Diet suggests very specific types of food, 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 gluten-free diet, you should know that the Blood Type Diet doesn’t ban gluten. You may be able to make gluten-free choices if you read food labels carefully.
Level of effort: high
You may need to limit your food choices. Your blood type will decide your shopping list and your choices when eating out. If you live with people who have different blood types, meal planning may be hard. Special packaged foods, however, aren’t 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 follow the Blood Type Diet on your own.
Exercise. The Blood Type Diet suggests 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 and former director of nutrition at WebMD, 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 getting rid of 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 useful 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 heart 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 that are in other parts of the diet plan are lower in saturated fat, however.
“If you have heart disease or 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, many grocery list items aren’t included in the Blood Type 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 eating less processed foods can be good for your health, not all processed foods are bad. Milk and wheat, for example, need to be processed for safety reasons and to make them easier to digest.
Finally, Zelman notes that it’s OK if you can’t always buy the organic versions of food recommended by the Blood Type Diet, which can be costly. “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 your family tries the Blood Type Diet, it might be a challenge to meet everyone’s nutritional needs, especially if you strictly follow it. Zelman gives the example of avoiding dairy (part of the type O and A diets), which could be harmful to kids.
“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, and eating lean meats and lots of fruits and vegetables — are all good for everyone’s overall health, Zelman says. But once you start customizing the diet for your family, it’s not really the Blood Type Diet anymore.
“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 Meal Ideas
Here are some foods you could eat based on D’Adamo’s Blood Type Diet:
Meal ideas for type O blood
Breakfast: Mango smoothie made with pineapple juice, mango, banana, frozen blueberries, and ice cubes
Lunch: Black bean soup with ground beef and rice
Dinner: Baked sesame chicken, served with rice, salad, or spelt noodles
Meal ideas for type A blood
Breakfast: Tofu scramble with grated carrot and zucchini
Lunch: Vegetarian lentil soup
Dinner: Spinach feta rice
Meal ideas for type B blood
Breakfast: Applesauce cake made with crushed almonds, quinoa flakes, flaxseeds, and chia seeds
Lunch: Egg and seaweed soup
Dinner: Grilled lamb chops with mint-yogurt sauce
Meal ideas for type AB blood
Breakfast: Egg and banana pancakes
Lunch: Tofu and vegetable stir-fry
Dinner: Pumpkin lentil dal
Takeaways
The idea behind the Blood Type Diet is that your specific blood type makes certain foods easier for you to digest. But there's no scientific proof that this way of eating works. If you lose weight on the Blood Type Diet, it’s most likely because many of the foods it includes, such as fruits and vegetables, are healthy options. It also asks you to avoid ultra-processed foods, such as packaged sweets and fast foods, that lead to weight gain. If you want to try the Blood Type Diet, check with your doctor first, especially if you have an ongoing health condition.
Blood Type Diet FAQs
Is the Blood Type Diet healthy?
While there’s no proof that the Blood Type Diet works or is harmful, it’s better to consider your family’s health history (such as whether certain diseases run in your family) rather than your blood type when it comes to choosing the diet that’s best for you.
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. The Blood Type Diet claims that each type has its own benefits and potential health considerations.
What foods should O+ blood type avoid?
If you’re trying to stick to the Blood Type Diet, you should eat less dairy, beans, and legumes. Gluten could also cause you to gain weight.
What are the best foods for A positive blood type diet?
All A blood types are advised to stick to a largely vegetarian diet, such as soy protein, whole grains, and vegetables. D’Adamo believes that fresh and organic types are best.
