The short answer is no: the blood type diet has not been shown to improve health, and the research that exists does not support the idea that eating for your blood type does anything special. A 2013 systematic review in the American Journal of Clinical Nutrition found no studies showing health benefits from blood type…
The short answer is no: the blood type diet has not been shown to improve health, and the research that exists does not support the idea that eating for your blood type does anything special. A 2013 systematic review in the American Journal of Clinical Nutrition found no studies showing health benefits from blood type diets, and a 2014 study in PLoS ONE of 1,455 adults found that any benefit tracked with how closely people followed a healthy pattern, not with their blood type. For patients across Pembroke Pines and South Florida who are asking whether a diet by blood type is worth trying, here is what the evidence shows, why some people still feel better on it, and what to do instead.
blood type diet chart[/caption>
Searches for a blood type diet chart or blood type diet food list usually want a quick lookup. Here is a pattern-level summary of what the diet tells each type to eat, as described by Cleveland Clinic and Ohio State Health, next to what testing has found. We have deliberately kept it at the pattern level rather than reproducing full food-by-food lists, because the lists themselves are not supported by research.
| Blood type | What the diet claims | What testing found |
|---|---|---|
| Type O | Lean meats and a higher-protein pattern | Tested in the Toronto study; any association was independent of ABO genotype |
| Type A | A largely vegetarian pattern | Adherence was linked to better cardiometabolic markers, but not because of blood type |
| Type B | A broader, omnivorous pattern | Tested in the Toronto study; no support for a blood-type-specific benefit |
| Type AB | A broader, omnivorous pattern | Adherence was linked to better cardiometabolic markers, but not because of blood type |
The pattern in the last column matters more than any single row. In every case, the finding was the same: a healthier eating pattern helped, and blood type did not change who it helped.
The blood type diet is an eating plan that assigns foods to eat and avoid based on whether your blood type is O, A, B, or AB. According to Cleveland Clinic, it was introduced by naturopathic physician Peter D’Adamo in 1996. The premise, as its author states it, is that each blood type is suited to the foods of a particular era of human evolution. His book, Eat Right for Your Type, made the idea widely known; the University of Toronto reports that it sold more than 7 million copies worldwide.
It is important to separate the premise from the evidence. The evolutionary story is the diet’s own claim. It is a diet by blood type built on an idea, and the sections below look at whether anyone has tested that idea.
The most direct answer to “is the blood type diet legit?” comes from a systematic review by Cusack and colleagues in the American Journal of Clinical Nutrition. The authors searched the Cochrane Library, MEDLINE, and Embase. They identified 16 articles from 1,415 screened references, and only one met the selection criteria. That one study looked at LDL-cholesterol response to a low-fat diet by a different blood group system (MNS), so it did not directly answer the question. The reviewers found no studies of the health effects of ABO blood type diets and concluded that no evidence currently exists to validate the purported health benefits.
Researchers led by Jingzhou Wang and Ahmed El-Sohemy analyzed data from 1,455 adults aged 20 to 29 (993 women and 462 men) in the Toronto Nutrigenomics and Health study. Participants completed a 196-item food frequency questionnaire, and the team scored each person’s adherence to each of the four blood type diets. Adherence to some of the diets, notably the Type A and Type AB diets, was associated with better cardiometabolic markers such as cholesterol and triglycerides. Crucially, those associations did not depend on the participants’ ABO genotype. A person with Type O blood did as well on the “Type A” pattern as a person with Type A blood. That result does not support the theory.
The same research group later published “ABO Genotype Does Not Modify the Association between the ‘Blood-Type’ Diet and Biomarkers of Cardiometabolic Disease in Overweight Adults” in the Journal of Nutrition (2018). As the title states, the conclusion matched the earlier study, this time in overweight adults.
In a University of Toronto news release, El-Sohemy said that the response to any of these diets “has absolutely nothing to do with their blood type and has everything to do with their ability to stick to a sensible vegetarian or low-carbohydrate diet.”
Honest reporting means naming the limits. The Toronto analysis was cross-sectional, meaning it looked at a snapshot rather than following people over time. Its participants were young adults. And there is no randomized trial we are aware of that assigns people to a blood-type-matched versus mismatched diet and follows them. Absence of evidence is not proof that no benefit could ever exist. But the core claim of the theory, that matching food to blood type improves health, has failed the tests that do exist, and nobody has produced supporting studies.
diet based on blood type[/caption>
If the theory does not hold up, why do so many people report good results? Ohio State Health attributes any weight loss on the plan to calorie restriction and whole-food eating. That fits the Toronto finding: people who follow a structured plan with fewer processed foods tend to see better markers, whatever label the plan carries. A plan with clear rules can also make it easier to stay consistent, which is the point El-Sohemy makes.
This is why blood type diet weight loss stories should be read with care. Weight change on any plan depends on how much you eat, what you eat, and how long you keep it up. If you want to understand how those pieces fit together, our guides on nutrition for weight loss and on how much of a calorie deficit is too much are a better place to start. Results may vary, and no eating pattern works the same way for everyone.
For a generally healthy adult, trying a plan that emphasizes vegetables, lean protein, and whole foods is unlikely to cause harm by itself. The concern is the elimination lists. A plan that tells you to avoid entire food groups because of your blood type, with no medical reason, can leave gaps in what you eat. Cleveland Clinic also notes a concern about the Type B pattern and saturated fat, and reports that its dietitian sees no scientific evidence for the diet.
Anyone with diabetes, kidney disease, or a heart condition, anyone who is pregnant, and anyone taking prescription medications should not restructure their diet without input from their clinician. A rigid list cannot account for your labs, your medications, or your medical history. If you are weighing structured eating against a supervised plan, our comparison of medical weight loss versus diet plans explains the differences, and our page on why diet plans often fall short covers what tends to go wrong.
The o positive blood type diet is the most-searched version, so it deserves a direct answer. It gets no exemption. The studies above tested the diets designed for all four blood types, and the conclusion did not change by type. Whether your blood type is O positive, A negative, or anything else, the research gives no reason to choose your foods by blood type.
You do not have to be a researcher to spot a weak diet claim. Before you commit to any plan, ask these five questions:
Cleveland Clinic points people toward established patterns such as Mediterranean and DASH-style eating. For everyday ideas, browse our recipes, see answers to common questions in our weight loss FAQ, or read more on our blog. If you have tried structured programs before, you may also find our approach to breaking the diet cycle useful.
A blood type is one data point. A real plan starts with your medical history, your lab work, your medications, and what you want to achieve. That is the idea behind the CardioMender approach. At Cardiomender Weight Loss & Aesthetics, every program is run under medical supervision, and the plan is built around the individual patient rather than a category.
CardioMender has been helping patients with weight loss since April 2009, well before the current wave of trends. Care is in person at our Pembroke Pines clinic, not just a prescription by video, and the team supports patients with nutrition guidance, lab work, B-vitamin injections, and ongoing monitoring. The aim is lifestyle change and maintaining results over time, not dependence on any one product. You can read about our weight loss program, meet our team, see what other patients say in patient reviews, or learn about medical weight loss in Pembroke Pines. Results may vary, and every plan starts with an evaluation.
It is an eating plan that assigns foods to eat and avoid according to your ABO blood type. It was introduced by Peter D’Adamo in 1996 and popularized in his book Eat Right for Your Type. Its evolutionary premise is the author’s own claim and has not been supported by research.
Not according to the research we reviewed. A 2013 systematic review found no evidence to validate the purported health benefits, and a 1,455-person study found that benefits tracked with diet adherence, not blood type.
The evidence we reviewed gives no reason to set your diet by blood type. If you have a specific medical condition, your clinician can advise on what to eat based on your diagnosis and labs, not on your blood group.
Emphasizing whole foods is generally reasonable, but strict elimination lists can drop whole food groups without a medical reason. People with diabetes, kidney disease, or heart conditions, those who are pregnant, and those on medications should talk with a clinician before changing their diet.
Some people lose weight on it, but Ohio State Health attributes that to calorie restriction and whole-food eating, not to blood type. Results may vary.
There is no best diet for a blood type. Evidence-supported patterns, such as the Mediterranean and DASH-style approaches Cleveland Clinic recommends, are worth discussing with your clinician, who can tailor them to you.
Yes, especially if you have a health condition or take medication. A clinician can review your history and labs and help you build a plan you can keep up.
Ready for a plan built around you instead of your blood type? Serving patients from Pembroke Pines and across South Florida at our Pembroke Pines, FL clinic, Cardiomender Weight Loss & Aesthetics offers medically supervised care. Request an appointment or call (954) 799-6439 to schedule your consultation.
Our physician-supervised weight loss and aesthetic programs are designed around your unique body, goals, and lifestyle.
