{"id":29892,"date":"2026-05-19T06:51:20","date_gmt":"2026-05-19T13:51:20","guid":{"rendered":"https:\/\/foodrevolution.org\/?p=29892"},"modified":"2026-05-19T06:51:22","modified_gmt":"2026-05-19T13:51:22","slug":"does-science-support-the-blood-type-diet","status":"publish","type":"post","link":"https:\/\/foodrevolution.org\/blog\/does-science-support-the-blood-type-diet\/","title":{"rendered":"Does Science Support the Blood Type Diet?"},"content":{"rendered":"

In the 17th century, the European medical world was abuzz with the possibility that blood could be transfused<\/a> from one organism to another. The British had done some dog-to-dog transfusions, and their archrivals, the French, decided to up the ante by transfusing lambs\u2019 blood into human beings. (I don\u2019t know which was worse, to be the lamb or the human in that experiment!)<\/p>\n

The court physician to King Louis XIV, an ambitious experimenter named Jean-Baptiste Denis, tried in 1668 to cure an infamous Paris \u201cmadman\u201d by giving him serial transfusions. When the second procedure proved fatal, with the subject shaking in a violent fit<\/a> and dying the next day, Denis was arrested. After a trial and inquiry, the practice of transfusion \u2014 even human-to-human \u2014 was prohibited, and it remained a rare occurrence for the next 150 years.<\/p>\n

Although the reasons for the man\u2019s death were not understood until the late 19th century, it\u2019s pretty clear that the problem was what\u2019s known as a hemolytic transfusion reaction. Which is to say, the man\u2019s immune system rejected the infused blood, killing the red blood cells as if they were dangerous foreign invaders. <\/span><\/p>\n

In 1901, biologist Karl Landsteiner found the mechanism behind this potentially deadly reaction. He discovered different kinds of antibodies in human blood, which gave rise to different blood types. He named these types A, B, and O (and a fourth, AB, was identified a year later).<\/p>\n

This discovery has saved a lot of lives, making possible the safe transfusion of blood for people in a wide variety<\/a> of dire circumstances: serious injuries, surgeries, some cancer treatments, high-risk childbirths, and blood disorders. <\/span><\/p>\n

It\u2019s also given rise to a movement that claims your blood type is a key factor in determining what kind of diet you should eat, how you should move, and even what baseline personality you will exhibit.<\/p>\n

The Blood Type Diet has been around since the 1980s. Its core thesis is that each blood type requires a distinct diet and lifestyle to achieve optimal health. It even claims that blood types are linked to distinct personality profiles, and that learning about and embracing your \u201ctype\u201d can lead to the best possible life. <\/span><\/p>\n

Millions of people have adopted the Blood Type Diet in the hopes of losing weight and improving their overall well-being. But does your blood type really have anything to do with customized nutrition recommendations, or is this just another fad diet? Is there any scientific basis for eating for your blood type? Or is the Blood Type Diet as unproven as (although far less hazardous than) trying to cure insanity with lambs\u2019 blood?<\/p>\n

What Is the Blood Type Diet?<\/span><\/h2>\n
\"nutritionist
iStock.com\/kitzcorner<\/figcaption><\/figure>\n

The Blood Type Diet was created by Dr. James D\u2019Adamo, a naturopathic doctor, in the 1980s and then popularized by his son and fellow naturopathic doctor, Dr. Peter J. D’Adamo. It continues to garner attention today, although its popularity has been declining over the past decade. <\/span><\/p>\n

Based on your blood type \u2014 A, B, AB, or O \u2014 the program provides guidelines for the best types of foods to eat, what foods to avoid, stress management tips, and the most beneficial types of exercise for you. In other words, the optimal way of eating for someone with type A blood differs markedly from that of someone with blood type B. And so too for ABs and Os.<\/p>\n

The Blood Type Diet became wildly popular after Dr. Peter D\u2019Adamo published his book Eat Right 4 Your Type<\/em><\/a> in 1996. It\u2019s been followed by many other volumes, including blood type cookbooks and supplement guides. But the original book remains a best seller, with over 7 million copies sold. And in addition to books, Dr. D\u2019Adamo built his version of the Blood Type Diet into a major business enterprise<\/a>, selling a long list of branded dietary supplements, teas, nutrition programs, and even a skincare line. <\/span><\/p>\n

Clearly, a lot of people are buying it (figuratively and literally). But what are they buying? A key to health and longevity, or distracting nonsense? Let\u2019s take a look at D\u2019Adamo\u2019s claims and the evidence for or against them.<\/p>\n

Blood Types and Their Diet and Lifestyle Claims<\/span><\/h2>\n
\"vital
iStock.com\/metamorworks<\/figcaption><\/figure>\n

The Blood Type Diet claims that by following your tailored recommendations based on your blood type, you can learn how to handle stress most effectively, manage your weight, avoid disease, and eat better. Let\u2019s take a closer look.<\/p>\n

Below are the basics of what the program says you should eat<\/a>, how you should exercise, and what other lifestyle traits you should adopt, according to which of the four blood types you have.<\/p>\n

Important disclaimer<\/b><\/p>\n

The details shared below are simply intended to clarify what the Blood Type Diet recommends for its users, rather than what health professionals recommend or what we at Food Revolution Network advocate.<\/em><\/p>\n

Blood Types: A Summary<\/span><\/h3>\n

Type A: <\/b>Those with <\/span>type A blood<\/span><\/a>, according to D\u2019Adamo, have an extra-sensitive immune system and need to avoid stress triggers and eat a mostly vegetarian diet to \u201cenjoy the innately settled, creative state\u201d characteristic of <\/span>type As<\/span><\/a>.<\/span><\/p>\n

Type B: <\/b>According to D\u2019Adamo, people with <\/span>Blood Type B<\/span><\/a> are innately adaptable and open. They have a strong immune system and \u201cbalanced\u201d nervous system, and will benefit from a mix of meditative activities and more intense physical exercise. <\/span>Type Bs<\/span><\/a> are prescribed a very meat-heavy, omnivorous diet that excludes some grains and chicken.<\/span><\/p>\n

Type AB: <\/b>Blood Type ABs<\/span><\/a> are told to address their highly sensitive digestive tract through a mixed diet: tofu, seafood, greens, and kelp are in, while no-nos include chicken, corn, kidney beans, and buckwheat. They should also keep their nervous system calm through centering physical activity and moderate exercise.<\/span><\/p>\n

Type O: <\/b>According to the program, <\/span>Blood Type Os<\/span><\/a> have a hardy digestive tract and a strong immune system. On the flip side, they can overreact to novel conditions with anger and manic episodes. They are supposed to eat a high-protein diet and avoid most grains, legumes, and dairy products (leaving red meat as a staple) so they can be the \u201cstrong, self-reliant leader\u201d their blood type predicts.<\/span><\/p>\n

What the Blood Type Diet Gets Right<\/span><\/h2>\n
\"arrangement
iStock.com\/Artemidovna<\/figcaption><\/figure>\n

Before we get to the problems with the Blood Type Diet, let\u2019s acknowledge some of the positives.<\/p>\n

Some Blood Type Diets Limit Animal Products<\/span><\/h3>\n

First, some blood types are encouraged to limit consumption of animal products and eat \u201chealthier.\u201d In fact, Dr. James D\u2019Adamo originally tried<\/a> prescribing a low-fat, vegetarian diet to all his patients. But when they didn\u2019t all consistently do well on that diet, he theorized that individual blood types might have something to do with it. So, the origins of the diet did come from prioritizing plant foods over animal foods for optimal health.<\/p>\n

Even though a plant-based diet isn\u2019t at the forefront of this program anymore, the Blood Type A diet is still primarily vegetarian, with the additions of turkey and seafood.<\/p>\n

Dr. D\u2019Adamo also recommends eating organically grown food<\/a>, which can help reduce exposure to pesticides and contribute to a healthier, more ethical world.<\/p>\n

The Blood Type Diet Encourages Lifestyle Adjustments<\/span><\/h3>\n

Fortunately, the Blood Type Diet recognizes that diet and lifestyle affect health and the development of disease. Ultimately, it does focus on diet and lifestyle factors to improve health and prevent disease. And it encourages people to think about these things as interconnected.<\/p>\n

Incorporating lifestyle is an important approach to take with diet programs, as global research<\/a> shows that \u201cThe combination of four key factors \u2014 maintaining a healthy weight, exercising regularly, following a healthy diet, and not smoking \u2014 seems to be associated with as much as an 80% reduction in the risk of developing the most common and deadly chronic diseases.\u201d<\/p>\n

Blood Type Diets Are a Form of Personalized Nutrition<\/span><\/h3>\n

Lastly, the program is a positive example that a one-size-fits-all approach to nutrition just doesn\u2019t work. Instead, it\u2019s a type of personalized nutrition<\/a> that at least attempts to take into account an individual\u2019s genetic, phenotypic (i.e., blood type), medical, and nutritional factors to determine the best guidance.<\/p>\n

Research has validated the benefits of personalized nutrition. In a 2015 randomized controlled trial<\/a> published in the journal Cell, researchers monitored the blood glucose trends of 800 people over 1 week, measuring responses to 46,898 meals. They found high variability in the glucose response to identical meals, suggesting that universal dietary recommendations may not benefit everyone. (You have to admire the researchers\u2019 self-control; I would have a hard time not insisting that they reach an even 50,000.)<\/p>\n

There\u2019s certainly precedent for personalized nutrition. But the best approach likely has more to do with multiple factors like blood markers, dietary habits, body measurements, physical activity, and gut microbiota than blood type on its own.<\/p>\n

Other factors, like age and stage of life, also influence someone\u2019s nutritional needs. A perfect example of this is the difference in recommended nutritional needs among children, teens, adults, pregnant and lactating women, and seniors. (As I was editing this article, I misread the last word of that sentence as \u201csailors,\u201d and got seriously confused for a second.)<\/p>\n

Problems with the Blood Type Diet<\/span><\/h2>\n

Although the Blood Type Diet gets some things right, it also presents several significant problems. The overarching issues are a lack of any coherent explanation for why blood type should determine so much about a person\u2019s dietary choices and virtually no credible supporting evidence. Let\u2019s dive deeper. <\/span><\/p>\n

A Focus on Genetics<\/span><\/h3>\n
\"test
iStock.com\/busracavus<\/figcaption><\/figure>\n

Whether you\u2019re an A, B, AB, or O, genetics determines your blood type. But research suggests that genes are just one piece<\/a> of the puzzle when it comes to your health and rarely determine your destiny by themselves. <\/span><\/p>\n

After all, your genetics don\u2019t account for behavior, environmental influences, or even current health conditions that may need to be taken into consideration when looking at diet, exercise, and lifestyle choices. You don\u2019t have a gene for going for a walk, or ordering a salad instead of a cheeseburger, or whether you live in a food desert<\/a>.<\/p>\n

(Tangent alert: That last sentence reminded me of a joke by Jonathan Katz: \u201cScientists have found the gene for shyness. They would have found it years ago, but it was hiding behind a couple of other genes.\u201d<\/em>)<\/p>\n

Furthermore, while specific genetic variants can influence<\/a> how you respond to certain foods and nutrients, the dynamic also works in reverse \u2014 the foods you eat can change how your genes are expressed. A person genetically predisposed to type 2 diabetes can often avoid the disease by eating a high-fiber, plant-based diet composed mostly of whole foods. But another person without those genes can develop a galloping case of type 2 diabetes by eating the standard American diet (SAD). <\/span><\/p>\n

Glosses Over Health Impacts of Animal Products<\/span><\/h3>\n
\"composition
iStock.com\/Monticello<\/figcaption><\/figure>\n

Next, the Blood Type Diet doesn\u2019t address the numerous health issues associated with eating animal products, outside of whether doing so aligns with a particular blood type. <\/span><\/p>\n

While it emphasizes whole foods and encourages buying organic, most of the recommended eating patterns still prioritize animal products. The type A diet is mainly vegetarian because these individuals are purportedly unable to metabolize animal protein well, not because animal protein is generally problematic for humans.<\/p>\n

Decades of research show that eating more plants and fewer animal products tends to be better for your health<\/a>. And this research includes people of all blood types, all ages and life stages, and countless other factors that make us unique individuals. <\/span><\/p>\n

For example, eating a diet high in meat and dairy products<\/a> is associated with the development of an array of chronic diseases. Meat is known to promote inflammation<\/a> and can trigger the production of a metabolite called TMAO<\/a>, which has been associated with the development of inflammatory conditions like heart disease, type 2 diabetes, chronic kidney disease, cancer, and liver disease. <\/span><\/p>\n

Animal products are naturally high in saturated fat<\/a>, which can promote the buildup of fat in your arteries and raise your LDL cholesterol levels, increasing the risk of heart disease<\/a>. Also, because animals are high up the ecological food chain, their bodies become concentrated repositories of hormones, antibiotics<\/a>, and harmful environmental contaminants, such as persistent organic pollutants<\/a>. No blood type can protect you from the high toxic load you\u2019ll encounter when you consistently eat that high on the industrial food chain. <\/span><\/p>\n

When you zoom out a little, large-scale animal agriculture harms not just the individuals who consume its products but all humans (and most other species) through its considerable greenhouse gas emissions<\/a>. In fact, if the growth of the global meat and dairy industry continues as projected, the livestock sector as a whole could contribute 80% of the planet\u2019s annual greenhouse gas budget<\/a> by 2050. I don\u2019t care how much kale you eat; it\u2019s hard to be a truly healthy person on a sick planet.<\/p>\n

Emphasizes Supplements<\/span><\/h3>\n
\"spoon
iStock.com\/ronstik<\/figcaption><\/figure>\n

The Blood Type Diet heavily promotes its own line of supplements for each blood type and for specific health goals, such as weight loss, immune support, increased energy, or stress management. <\/span><\/p>\n

They also have a supplement advisor program<\/a> designed to \u201cenhance your quality of life and well-being.\u201d It weighs factors such as age, gender, blood type, and perceived areas of improvement, and lacks input from an actual health care advisor. <\/span><\/p>\n

While there are certainly scenarios where supplements are helpful<\/a> or even necessary, in general, most nutrition experts are in agreement<\/a> that you should be getting most of your nutrients from food, especially whole foods. It\u2019s right there in the word: They\u2019re supplementary, not primary.<\/p>\n

Advises Against Lectins<\/span><\/h3>\n
\"close-up
iStock.com\/temele<\/figcaption><\/figure>\n

The Blood Type Diet advises against<\/a> consuming lectins, a type of protein found in certain plants, including legumes, tomatoes, potatoes, soy, barley, eggplant, wheat, rice, and fruit. Thanks to the popularity of the anti-lectin diet in the 2017 book The Plant Paradox<\/em> by Dr. Steven Gundry, many people have become convinced that lectins damage their gut microbiome and overall health.<\/p>\n

The Blood Type Diet goes even further, claiming that lectins can specifically target different blood types and that eating the \u201cwrong\u201d types can lead to agglutination \u2014 or clumping together \u2014 of red blood cells, releasing toxins into the blood. Upon closer examination<\/a>, though, lectins largely trigger the same reactions across blood types. <\/span><\/p>\n

There\u2019s some evidence that certain plants may have blood group antigens. But most of the testing was done on seed extracts, not the plant itself, and this theory hasn\u2019t been tested with the impact of these lectins on actual people, only on blood cells<\/a>. Also, most of the foods to be avoided, such as beans and lentils, are typically eaten well-cooked (which significantly decreases lectin activity<\/a>), while the studies have been done on raw beans. This is a little like arguing that beans are bad because you can break your teeth trying to eat them raw.<\/p>\n

Overall, concerns about lectins are largely overblown, and most people can consume them safely. Just remember \u2014 and you heard it here first \u2014 to cook your red beans before chowing down. <\/span><\/p>\n

The main problem with avoiding lectin-containing foods is that they\u2019re some of the healthiest things you can eat: full of fiber, vitamins, minerals, and disease-fighting plant compounds. In fact, in small amounts (the amounts you\u2019re likely to get when you eat a variety of plant foods daily), lectins themselves appear to be beneficial. Avoiding them, as the Blood Type Diet dictates, could actually put you at risk for developing nutrient deficiencies. For more on lectins, read our article here<\/a>.<\/p>\n

Lacks Scientific Evidence<\/span><\/h3>\n
\"blood
iStock.com\/PonyWang<\/figcaption><\/figure>\n

One major systematic review<\/a> evaluated the claim that adherence to blood type diets provides health benefits. The researchers scoured the scientific literature and found 16 relevant studies. Only 1 of them made it past the inclusion criteria; the other 15 were excluded because they either didn\u2019t study people following a specific blood type diet, didn\u2019t test a diet designed to improve health, or didn\u2019t measure clear health results.<\/p>\n

And that one study<\/a> that did satisfy those criteria? It found no evidence validating any purported health benefits associated with blood type diets.<\/p>\n

Another study<\/span><\/a> specifically tried \u201c…to determine the association between blood type diets and biomarkers of cardiometabolic health and whether an individual’s ABO genotype modifies any associations.\u201d The authors found that following certain blood type diets \u2014 but not all \u2014 reduced cardiometabolic risk factors. However, these associations were independent of an individual’s blood type, so the findings do not support the blood type diet hypothesis.<\/span><\/p>\n

A diet based predominantly on whole plant foods, on the other hand, has been shown time and time again to reduce risk for chronic diseases and even reverse conditions like heart disease and type 2 diabetes in a great many people. And this is true regardless of blood type.<\/p>\n

For example, a 16-week randomized clinical trial<\/a> published in 2021 looked at the benefits of a plant-based diet compared with a control (omnivorous) diet. It also included a secondary analysis to see if blood type had any effect on the outcomes, since, according to Dr. D\u2019Adamo, only type A is supposed to thrive on a mostly plant-based diet. The researchers found that blood type did not affect patient outcomes. They also found that all blood types experienced improved weight loss, and overweight adults experienced improvements in cardiometabolic health, from the diet change alone.<\/p>\n

Unlike the Blood Type Diet, there\u2019s evidence \u2014 an overwhelming amount, actually \u2014 suggesting that a plant-based diet is beneficial for you<\/a>, regardless of your blood type. <\/span><\/p>\n

(Which gives me an idea: maybe I should write four identical books about the health benefits of a whole foods, plant-based diet, and market each one to a different blood type. Maybe that\u2019s one way to sell tons of books and provide science-based guidance at the same time!)<\/p>\n

That\u2019s not to say blood type is irrelevant and we should stop caring about it at all. Certain blood types have a higher<\/a> risk of contracting COVID-19, and are at increased<\/a> risk of problematic outcomes when they do get it. These findings tell us that blood type may influence susceptibility to certain diseases. What they do not suggest is that people of different blood types should eat differently. Blood type is not destiny \u2014 and regardless of your type, healthy diet and lifestyle choices remain beneficial for just about everyone.<\/p>\n

The Verdict on Diets Based on Blood Type<\/span><\/h2>\n

Though flashy and intriguing, the Blood Type Diet is not supported by meaningful scientific data. There are currently no studies showing that choosing foods based on your blood type is good for you. Aspects of the protocol can be helpful, such as eating more whole organic foods, exercising more, and practicing stress management.<\/p>\n

But restricting foods because of lectins or other perceived threats related to blood type, or eating an abundance of animal products, may, in fact, contribute to nutritional deficiencies or the development of disease. Thousands of studies show that the vast majority of people, of all blood types, are better off choosing a whole foods, plant-based diet \u2014 one that is rich in a diversity of whole grains, vegetables, fruits, nuts, seeds, and legumes, and with minimal or no animal products.\u00a0<\/span><\/p>\n

The best reason to know your blood type is to give or receive blood safely, and not to decide what to put on your plate.<\/span><\/p>\n

Tell us in the comments:<\/h4>\n