The Truth Behind What Blood Types Can't Eat Meat?

November 6, 2025 •

3 min read

According to a 2013 systematic review published in the American Journal of Clinical Nutrition, there is no scientific evidence to validate the health benefits of the blood type diet. This widely debunked dietary theory, not any scientific fact, is the only source claiming certain blood types can't eat meat.

Quick Summary

This article explores the unproven blood type diet, addressing the myth that specific blood types must avoid meat. It presents scientific evidence refuting these claims, focusing on why personalized nutrition is based on proven health factors rather than blood type.

Key Points

Blood type does not determine diet: Scientific studies have found no evidence to support the claim that certain blood types cannot or should not eat meat.
The blood type diet is a theory, not science: The concept was proposed by a naturopathic physician and lacks validation through peer-reviewed research.
Positive health outcomes are due to healthier habits: Any improvements experienced by followers are linked to generally healthier eating (more whole foods, fewer processed) rather than blood type.
Lectins are not a significant threat: The theory that blood-type-incompatible lectins cause harm is unsubstantiated, as cooking typically neutralizes lectins.
Focus on evidence-based nutrition: Lifestyle, genetics, age, and pre-existing health conditions are the real determinants of personalized nutritional needs.
There are no blood types that can't eat meat: There is no medical or scientific reason for a healthy person to avoid meat based solely on their blood type.

The Origins of the Blood Type Diet

The idea that your blood type should dictate your diet was popularized by naturopathic physician Dr. Peter J. D'Adamo in his 1996 book, Eat Right 4 Your Type. This theory suggests that each blood type (A, B, AB, and O) evolved differently and requires a unique diet. D'Adamo's core premise centers on lectins, proteins he claimed could harmfully interact with specific blood types.

Based on these ideas, D'Adamo outlined specific dietary plans for each blood type:

Type A (The Cultivator): Recommended a mostly vegetarian diet, avoiding red meat, linked to the emergence of agrarian societies.
Type O (The Hunter): Advised a high-protein, meat-focused diet, reflecting hunter-gatherer ancestors.
Type B (The Nomad): Suggested a balanced diet including meat and dairy but excluding foods like chicken, corn, and wheat.
Type AB (The Enigma): Proposed a mixed diet combining A and B recommendations, favoring seafood, tofu, and dairy while limiting red meat and chicken.

It is important to note that these guidelines are based on D'Adamo's theories and not on peer-reviewed scientific studies.

Overwhelming Scientific Evidence Against the Blood Type Diet

Despite its popularity, the blood type diet is largely unsupported by scientific evidence and is widely regarded as a fad diet by the medical community. Numerous studies and reviews have failed to validate its core claims.

A 2013 systematic review in the American Journal of Clinical Nutrition found no scientific studies demonstrating the health benefits of the blood type diet.
A 2014 study from the University of Toronto investigated the blood type diet and concluded that while participants showed some health improvements, these were independent of their blood type. This study directly refuted the blood type hypothesis.
The diet's central claim about blood-type-specific lectin reactions is flawed. Most lectins are destroyed by cooking, and those that remain typically react with all blood types, not just specific ones. Additionally, blood type does not alter fundamental digestive processes or nutrient absorption.

Factors That Actually Influence Dietary Needs

Instead of blood type, a healthy diet is genuinely influenced by scientifically validated factors. These include:

Age and Gender: Nutritional needs vary significantly with age and gender.
Activity Level: Physical activity levels impact caloric and protein requirements.
Genetics: While complex, individual genetic makeup can play a role in metabolism and health predispositions, distinct from blood type.
Overall Health: Existing medical conditions necessitate specific dietary adjustments.
Dietary Preferences: Personal choices, ethical considerations, and cultural factors are valid components of a healthy diet.

Blood Type Diet Claims vs. Scientific Consensus


Aspect	Blood Type Diet Claims	Scientific Consensus
Dietary Guideline	People with Type A blood must avoid meat and eat a vegetarian diet.	There is no scientific basis to suggest any blood type can't eat meat.
Mechanism	Lectins in certain foods cause agglutination (clumping) in specific blood types, leading to health issues.	Cooking destroys most lectins, and they are not blood-type specific.
Health Outcomes	Following the specific diet for your blood type leads to better health and weight loss.	Health improvements seen by followers are likely due to cutting out processed foods, not blood type.
Credibility	Based on evolutionary biology and anecdotal evidence.	Lacks scientific proof and is widely rejected by health experts as a fad diet.

Focusing on Evidence-Based Nutrition

Rather than an unsupported diet, health professionals recommend focusing on balanced, evidence-based nutrition. A diet rich in whole foods benefits everyone, regardless of blood type. Key principles of a healthy diet include:

Eating a diverse range of fruits and vegetables.
Incorporating whole grains, healthy fats, and lean proteins.
Minimizing processed foods, added sugars, and unhealthy fats.
Ensuring adequate nutrient intake.

Individual health history, lifestyle, and nutritional needs are the most crucial factors in dietary choices. Consulting a doctor or registered dietitian can provide a personalized and effective eating plan. Evidence-based diets like the Mediterranean or DASH diets have shown broad health benefits independent of blood type.

Conclusion

The claim that certain blood types, such as Type A, cannot eat meat stems from the unproven blood type diet theory and is not supported by scientific evidence. Any perceived health benefits from following this diet are likely due to the adoption of generally healthier eating habits, such as reducing processed food intake, rather than a person's blood type. For optimal nutrition, it is best to rely on evidence-based dietary advice from qualified health professionals tailored to individual needs, rather than pseudo-scientific claims. A systematic review in the American Journal of Clinical Nutrition provides further details on the lack of scientific support for the blood type diet.

Frequently Asked Questions

No, this is a claim from the unproven blood type diet. Scientific research has found no evidence to support the idea that people with Type A blood should avoid meat. A balanced diet, not blood type, is the key to good health.

The scientific and medical consensus is that the blood type diet is not supported by evidence. Multiple studies, including a 2013 systematic review, found no basis for the claims that following a diet based on your blood type improves health.

People who feel better on the blood type diet are likely benefiting from generally healthier eating habits. The diet's recommendations often involve cutting out processed foods and increasing fruit and vegetable intake, which improves health for everyone, irrespective of blood type.

Yes, following the blood type diet could be restrictive and lead to nutritional deficiencies. For example, the recommendation for Type O to avoid dairy could risk calcium deficiency, while avoiding nutritious foods like tomatoes for Type B individuals removes a valuable source of vitamin C.

When creating a diet plan, consider evidence-based factors like your age, gender, activity level, and existing health conditions. Consulting with a registered dietitian or doctor is the most reliable way to get a personalized and healthy eating plan.

There is no scientific evidence to show that blood type significantly affects how your digestive system functions or how you break down and absorb food. Digestion is a complex process influenced by a wide range of factors, not just blood type.

The blood type diet theory was developed by naturopathic physician Dr. Peter J. D'Adamo and popularized in his 1996 book, Eat Right 4 Your Type. The theory is based on the unproven concept of ancestral evolution and lectin interactions.