Understanding the Myth: What Blood Type Cannot Eat Meat?

December 20, 2025 •

3 min read

According to a 2013 review in the American Journal of Clinical Nutrition, there is no scientific evidence to support the claims of the blood type diet. The theory, popularized by Dr. Peter D'Adamo, suggests certain blood types, particularly type A, cannot eat meat, but this is a claim widely debunked by the medical community.

Quick Summary

The blood type diet suggests specific eating plans for each blood type, advising type A to avoid meat. However, scientific evidence consistently refutes these claims, affirming that all blood types can safely consume meat as part of a balanced diet. The diet is largely considered pseudoscience.

Key Points

Blood Type Diet Theory: The idea that certain blood types, like Type A, cannot eat meat originated from Dr. Peter D'Adamo's 1996 book, based on unproven ancestral and lectin theories.
No Scientific Evidence: Extensive scientific reviews, including one in the American Journal of Clinical Nutrition, have found no evidence to support the blood type diet's claims or link between blood type and dietary needs.
Meat is Safe for All Types: All blood types can safely eat meat as part of a balanced diet, provided there are no other health conditions or personal preferences influencing that choice.
Focus on Balanced Diet: Any health benefits from following the blood type diet are likely due to the elimination of unhealthy processed foods, not the blood type compatibility.
Consult a Professional: For accurate, personalized nutrition advice, it is best to consult a registered dietitian or medical professional rather than relying on unverified claims.
Pseudoscience: The blood type diet is widely considered a form of pseudoscience and not endorsed by mainstream medical professionals.

Unpacking the Origins of the Blood Type Diet

The idea that a specific blood type dictates dietary needs, particularly regarding meat consumption, originates from the blood type diet theory developed by naturopathic physician Dr. Peter D'Adamo. His 1996 book, Eat Right 4 Your Type, proposed that blood types A, B, AB, and O correspond to the eating patterns of human ancestors. According to D'Adamo, consuming foods incompatible with one's blood type can lead to health issues due to interactions with proteins called lectins.

D'Adamo's theory suggests that Type O blood, being the oldest, is aligned with a hunter-gatherer diet high in meat. Type A blood, linked to the rise of agriculture, is recommended to follow a vegetarian diet, thus suggesting that this blood type cannot eat meat. Type B is associated with nomadic diets including dairy, and Type AB is a mix of A and B.

The Scientific Verdict: Lack of Evidence

Despite its popularity, the blood type diet lacks support from mainstream medical and nutritional science. A comprehensive review in the American Journal of Clinical Nutrition found no evidence to validate the diet's effectiveness. Scientific studies have not established a link between blood type and optimal diet.

Criticisms from the scientific community include:

Lectins and Agglutination: The diet's premise about lectins causing blood cell clumping based on blood type is not supported by evidence; most lectins are destroyed by cooking and do not cause the specific reactions claimed.
Evolutionary Basis: The historical narrative connecting blood types to ancient diets is questioned by researchers and lacks factual backing.
Attributing Health Gains: Any positive health outcomes are more likely due to the diet's general emphasis on consuming fewer processed foods and more whole foods, rather than blood type-specific restrictions.
Genetic Oversimplification: Human nutritional needs are complex and influenced by numerous factors, not just a single genetic marker like blood type.

Blood Type Diet vs. Evidence-Based Nutrition

The blood type diet's recommendation for Type A individuals to avoid meat contrasts sharply with standard nutritional advice. While the diet claims this is necessary due to digestive incompatibility, evidence-based nutrition recognizes lean meats, poultry, and fish as valuable sources of protein and essential nutrients for everyone, regardless of blood type.

Comparison Table: Blood Type Diet vs. Mainstream Nutritional Advice


Feature	Blood Type Diet (Type A)	Mainstream Nutritional Advice
Stance on Meat	Avoid red meat; mostly vegetarian diet.	Lean meats, poultry, and fish are healthy protein sources for all.
Focus of Recommendations	Specific foods based on blood type and ancestral history.	Balanced intake of all food groups based on individual needs, health goals, and medical conditions.
Scientific Support	None. Considered pseudoscience.	Based on extensive research and long-term studies.
Risk of Nutrient Gaps	Possible deficiencies in iron, calcium, and B vitamins if not properly planned.	Addresses potential nutrient deficiencies and encourages balanced variety.
Reason for Health Gains	Alleged compatibility of lectins with blood type.	Weight loss and improved health due to reduced processed food intake.

A Balanced Perspective on All Blood Types and Meat

Scientific evidence confirms that all blood types can safely include meat in their diets, provided there are no other health or ethical reasons not to. Any perceived benefits from the blood type diet are likely due to its encouragement of consuming more whole foods and fewer processed items, a general principle of healthy eating. Adopting a balanced dietary pattern, such as the Mediterranean diet, which includes a variety of food groups with occasional red meat, is a scientifically supported approach to health.

Conclusion

In conclusion, the assertion that a specific blood type cannot eat meat stems from the scientifically unvalidated blood type diet. This theory, popularized by Dr. Peter D'Adamo, lacks empirical support and is not endorsed by the scientific community. There is no biological basis to link blood type to dietary requirements. A healthier and more sustainable approach involves following a balanced, evidence-based diet with a variety of whole foods, considering individual health needs and preferences. Consulting with a qualified healthcare professional is recommended for personalized nutritional guidance.

Visit the Academy of Nutrition and Dietetics for science-backed nutritional information.

Frequently Asked Questions

According to the unproven blood type diet, individuals with Type A blood are advised to avoid meat and follow a vegetarian diet, reflecting a supposed shift to an agrarian lifestyle.

No, there is no scientific evidence to suggest that any blood type physically cannot digest or metabolize meat. The human digestive system is not functionally altered by blood type.

The scientific and medical communities largely reject the blood type diet, considering it a form of pseudoscience with no credible evidence to support its claims.

Any health improvements are likely a result of generally healthier eating habits promoted by the diet, such as reducing processed foods, rather than a specific reaction to food based on blood type.

Yes, it is possible to get sufficient protein from other sources like legumes, beans, nuts, seeds, and certain plant-based proteins, regardless of your blood type.

No. The theory that lectins cause issues specific to certain blood types has been debunked. Most lectins are neutralized by cooking, and they do not cause blood cell agglutination as claimed.

A healthier approach is to focus on a balanced diet rich in whole foods, fruits, vegetables, and lean proteins, tailored to your individual health needs and preferences, in consultation with a healthcare professional.