What is the best diet for type A positive blood type?

December 19, 2025 •

3 min read

Despite its long-standing popularity, a comprehensive 2013 review published in the American Journal of Clinical Nutrition found no evidence to support the purported health benefits of the blood type diet. The diet, popularized by naturopath Peter D'Adamo, suggests specific eating patterns based on blood type, but is widely dismissed by mainstream nutrition experts as a fad.

Quick Summary

This article examines the popularized blood type diet specifically for type A positive individuals, detailing the recommended plant-based approach. It contrasts these claims with the consensus from the scientific and medical community that debunks a direct link between blood type and dietary needs, instead emphasizing a healthy, balanced diet for overall wellness.

Key Points

Blood Type Diet Theory: Popularized by Dr. Peter D'Adamo, this theory suggests type A individuals, known as 'agrarians,' thrive on a vegetarian diet due to perceived lower stomach acid and sensitive immune systems.
Lack of Scientific Support: A 2013 review in the American Journal of Clinical Nutrition found no scientific evidence to support the claims of blood type diets.
Health Benefits Independent of Blood Type: Any reported health improvements from following the type A diet, such as lower BMI or cholesterol, are likely due to cutting processed foods and eating more vegetables, a benefit seen across all blood types.
Healthy Eating Principles: A balanced diet focusing on whole foods, lean protein, healthy fats, and a variety of fruits and vegetables is recommended for everyone, regardless of blood type.
Avoid Unnecessary Restrictions: Excluding nutrient-rich foods based on the blood type diet is not scientifically supported and could lead to nutrient deficiencies.
Consult a Professional: For personalized dietary advice, it is best to consult with a registered dietitian or doctor, who can consider your specific health needs and goals.
Prioritize Whole Foods: The most significant takeaway is to reduce processed foods and increase whole food intake, which is a universally accepted health principle.

Understanding the Popular Type A Diet Theory

The blood type diet, proposed by Dr. Peter J. D'Adamo, suggests that individuals should eat based on their blood type. The theory claims that type A individuals, referred to as "agrarians," have a more sensitive immune system and lower stomach acid, making a primarily vegetarian or plant-based diet ideal for them. D'Adamo also suggests that certain proteins called lectins, found in foods, can interact negatively with specific blood types.

The Type A Positive Recommended and Avoided Foods (According to the Theory)

The type A diet theory recommends a diet focused on plant-based foods, including fruits like berries and citrus, and vegetables such as leafy greens, carrots, and garlic. Plant proteins like soy, legumes, and certain nuts are encouraged, along with whole grains like oats and quinoa, and healthy fats like olive oil.

Conversely, the diet advises type A individuals to avoid or limit red meat, most dairy, and specific vegetables like potatoes and tomatoes. Certain grains and nuts are also discouraged.

The Scientific Verdict on Blood Type Diets

The scientific and medical communities largely do not support the blood type diet. Research indicates a lack of evidence to validate its claims. A 2014 study found that while participants on the type A diet showed health improvements, these benefits were seen regardless of their blood type, suggesting they stemmed from eating a generally healthier diet rather than the blood type-specific plan. Experts emphasize that focusing on general healthy eating habits, such as reducing processed foods and increasing fruits and vegetables, benefits everyone.

Comparison of Blood Type Diet Claims vs. Evidence-Based Nutrition


Feature	Blood Type Diet (Claims for Type A+)	Evidence-Based Nutrition	Why the Difference?
Dietary Foundation	Primarily vegetarian, based on ancestral lineage.	Balanced, nutrient-dense, and personalized based on health goals.	The blood type diet's premise is based on a debunked evolutionary theory, while scientific nutrition focuses on individual needs, health conditions, and proven science.
Digestive Sensitivity	Assumes lower stomach acid necessitates a plant-based diet.	Digestive capability is influenced by various factors, including gut microbiome and overall health, not solely blood type.	There is no reliable evidence linking blood type to specific digestive enzyme levels or capabilities.
Food Restrictions	Recommends avoiding specific healthy foods like tomatoes, potatoes, and some seafood.	No healthy food groups are arbitrarily restricted. A varied diet is encouraged for a broad spectrum of nutrients.	Restrictive fad diets can lead to nutrient deficiencies, which is a key risk factor cited by nutrition experts.
Health Markers	Claims to reduce risk factors for diseases like cancer and heart disease.	Improvements in health markers are seen from eating more whole foods, not from a specific diet tailored to blood type.	Any health benefits reported are likely due to the elimination of unhealthy processed foods, which is a universal healthy habit.

What This Means for a Healthy Diet

Given the lack of scientific support for the blood type diet, individuals with type A positive blood should focus on general healthy eating principles. A balanced diet featuring whole foods, lean proteins, and healthy fats is the most effective approach for overall health. Prioritizing fruits, vegetables, whole grains, and legumes provides essential nutrients. Including lean protein sources and healthy fats like olive oil and avocados is also beneficial. It's also important to listen to your body and address any specific food sensitivities with a healthcare professional.

Conclusion: Focus on Evidence, Not Fads

The blood type diet lacks scientific backing. For those with type A positive blood, the best diet is a balanced, varied eating plan centered on whole, unprocessed foods. For personalized dietary advice, consult a registered dietitian or your doctor, who can provide guidance based on your individual health needs and goals. This approach ensures comprehensive nutrition without the risks of an unproven fad diet.

GoodRx provides more information on the efficacy of the blood type diet.

Frequently Asked Questions

No, the blood type A positive diet is not scientifically proven. Major scientific reviews, including one in the American Journal of Clinical Nutrition, found no evidence supporting the theory that blood type should dictate dietary choices.

According to the blood type diet theory, type A individuals should consume a mostly vegetarian diet, emphasizing vegetables, fruits, whole grains, and plant-based proteins like soy and legumes.

The diet advises against most meat and dairy products, certain vegetables like tomatoes and potatoes, and specific nuts and grains.

People who experience benefits from the blood type diet are likely seeing improvements from adopting generally healthy habits, such as eating more whole foods and less processed junk food. The positive effects are independent of their blood type.

Following any highly restrictive diet without scientific basis can potentially lead to nutrient deficiencies. Arbitrarily cutting out entire food groups can be risky and is not recommended by health experts.

A vegetarian diet is a healthy option for many people, but your blood type is not a valid reason to choose it. Base your dietary choices on personal health goals, ethics, and preferences, consulting with a professional if needed.

The best approach is to follow evidence-based nutrition guidelines, which focus on a balanced diet rich in whole foods, varied protein sources, and healthy fats, tailored to your individual needs.

While some claims have been made about increased risk for certain diseases in specific blood types, there's no evidence that diet can alter these risks based on blood type alone. A universally healthy diet is the best approach to mitigate disease risk for everyone.