Understanding the 'Why Can't Blood Type B Eat Chicken?' Diet Myth

October 13, 2025 •

4 min read

In 2013, a systematic review in the American Journal of Clinical Nutrition found no evidence to support the health benefits of the blood type diet. Despite this, the myth persists, especially the claim: 'Why can't blood type B eat chicken?' This article separates the science from the speculation to give you the facts.

Quick Summary

The unproven Blood Type Diet suggests individuals with blood type B avoid chicken. This guide explains the diet's basis in the unsupported lectin theory and presents overwhelming scientific evidence that debunks the claim.

Key Points

Diet Based on Flawed Theory: The prohibition of chicken for blood type B originates from the unproven Blood Type Diet theory by Dr. Peter D'Adamo.
Lectin Claim is Not Supported: The diet suggests a specific lectin in chicken causes blood agglutination in type B individuals, but scientific research has not validated this claim.
Widespread Scientific Rejection: Major scientific reviews, including one in the American Journal of Clinical Nutrition, have found no evidence supporting the Blood Type Diet's health benefits.
Reported Benefits Are Misattributed: Any positive health outcomes from following the diet are likely due to cutting out processed foods and eating more whole foods, not due to the blood type-specific restrictions.
Balanced Diet is Key: Evidence-based nutrition emphasizes a varied diet of lean protein, fruits, and vegetables, not restricting foods based on blood type.

The Origins of the Blood Type Diet and the Chicken Claim

The notion that blood type dictates dietary needs gained popularity with Dr. Peter D'Adamo's 1996 book, Eat Right 4 Your Type. The diet categorizes foods as 'highly beneficial,' 'neutral,' or to be 'avoided' based on a person's ABO blood type. For those with blood type B, Dr. D'Adamo proposed a balanced omnivore diet that includes certain meats, dairy, and vegetables but specifically restricts chicken. The core justification behind this ban is centered on a theory involving proteins called lectins.

The Lectin Hypothesis: A Flawed Rationale

Dr. D'Adamo's theory suggests that chicken contains a unique lectin that is 'agglutinating' for blood type B. Agglutination is the process of red blood cells clumping together. According to this hypothesis, when blood type B individuals consume this lectin, it supposedly attacks their bloodstream, which could lead to health issues such as immune disorders and strokes. This theory forms the basis for the diet's various restrictions for all blood types.

Why Science Rejects the Blood Type Diet

Despite its widespread popularity, the Blood Type Diet is widely considered pseudoscience by the medical community. Extensive research has failed to validate its foundational principles. A major systematic review conducted in 2013, which analyzed 1,415 scientific articles, concluded that there was no evidence supporting the health benefits of a blood type-based diet. Subsequent studies have also confirmed that any health improvements seen by followers are not linked to their blood type but are likely a result of simply shifting to a healthier, whole-foods diet and eliminating processed foods.

Furthermore, the lectin theory itself is based on misconceptions. While lectins exist in many foods, they are largely deactivated or destroyed by cooking and digestion. Any agglutinating effects observed in laboratory settings are not reflective of how the human body processes food. Experts emphasize that individual factors such as age, gender, activity level, and medical history are the most significant determinants of dietary needs, not blood type.

Comparing the Blood Type Diet vs. Evidence-Based Nutrition

To illustrate the difference in approaches, consider the comparison below:


Feature	Blood Type Diet (Type B)	Evidence-Based Nutrition
Core Principle	Avoidance of chicken due to a specific lectin believed to cause agglutination.	Chicken is a lean protein source, beneficial for overall health, and not restricted by blood type.
Dietary Focus	Restrictive, with an emphasis on eliminating or moderating foods based on blood type.	Inclusive, focusing on a varied and balanced intake of whole foods, including lean proteins like chicken.
Primary Evidence	Relies on the unproven theory of Dr. Peter D'Adamo.	Backed by extensive scientific research, clinical studies, and nutritional science.
Scientific Consensus	Widely considered a fad diet with no supporting scientific proof.	Emphasizes moderation, variety, and individual health needs for optimal well-being.
Health Impact	Any reported health benefits are likely due to the elimination of unhealthy processed foods, not blood type.	Supports long-term health, disease prevention, and sustainable wellness through balanced choices.

A Broader Perspective on Nutrition

Instead of focusing on arbitrary food restrictions like the chicken ban for blood type B, modern nutrition emphasizes a more holistic and evidence-based approach. A balanced diet should include a variety of lean protein sources, fruits, vegetables, and whole grains. For those who enjoy chicken, there is no scientific reason to avoid it, regardless of blood type. Other excellent protein sources include:

Fish: Many varieties, especially deep-sea fish, are rich in omega-3 fatty acids.
Legumes: Lentils, beans, and peas offer plant-based protein and fiber.
Dairy: For those without lactose intolerance, low-fat dairy products can be a source of protein and calcium.
Other Lean Meats: Lamb, goat, and turkey are all excellent alternatives for a varied diet.

Adopting a nutritious diet that aligns with proven health principles is more effective and sustainable than following a restrictive fad diet with no scientific basis. You can confidently enjoy chicken as part of a healthy lifestyle, provided it fits your personal health goals and preferences.

Conclusion: Focus on Facts, Not Fads

The claim that individuals with blood type B cannot eat chicken stems from the scientifically unproven Blood Type Diet. Based on a flawed theory about lectins and blood agglutination, this restrictive diet has been widely debunked by the medical and nutritional science community. Instead of worrying about your blood type, focus on building a well-rounded diet that includes a wide variety of whole, unprocessed foods. Why can't blood type B eat chicken? The short answer is: they can, and there is no credible science to suggest otherwise. Consult a registered dietitian or healthcare provider for personalized nutritional advice based on actual evidence.

For more information on evidence-based nutrition and the scientific critique of the blood type diet, consult the National Institutes of Health.

Frequently Asked Questions

The Blood Type Diet is a diet plan developed by naturopath Peter J. D'Adamo that claims a person's blood type (A, B, AB, or O) should dictate their dietary choices for optimal health. It assigns food recommendations and restrictions based on this theory.

No, there is no credible scientific evidence to support the Blood Type Diet. A major review in 2013 found no studies validating its claims, and health professionals widely consider it a fad diet.

Yes, people with blood type B can safely eat chicken. The restriction is based on a debunked and unproven theory, and chicken is a healthy source of lean protein for anyone, regardless of blood type.

Lectins are carbohydrate-binding proteins found in many foods, including plants. While the Blood Type Diet claims some lectins are harmful, cooking and digestion typically deactivate them. They are generally not a concern in a healthy, varied diet.

People who feel better on the diet likely benefit from eating more whole foods and fewer processed foods, not because of their blood type. The diets often involve healthier general eating habits, leading to improved health markers independent of blood type.

A more effective approach is to follow evidence-based nutritional guidelines that focus on a balanced intake of whole foods, lean proteins, and produce. Consult a registered dietitian for personalized advice based on your individual health needs.

Yes, following the diet strictly can lead to unnecessary nutrient restrictions and potentially unhealthy eating patterns. For example, some versions of the diet recommend avoiding dairy or other nutrient-rich foods, which could be detrimental.