Foods Blood Type B Negative People Should Avoid

December 1, 2025 •

4 min read

First popularized in the 1996 book 'Eat Right 4 Your Type,' the Blood Type Diet suggests a person's diet should be based on their blood type. For those wondering what foods should blood type B negative people avoid, the dietary plan specifies a list of meats, grains, legumes, and seeds to exclude based on the theory that certain lectins in these foods negatively impact Type B blood. However, it is important to note that the scientific community does not support this theory.

Quick Summary

This article explores the specific food recommendations for B negative individuals outlined in the controversial Blood Type Diet, highlighting the purported negative food groups and discussing the notable lack of scientific validation for this dietary approach.

Key Points

Blood Type Diet Theory: Peter D'Adamo's diet suggests specific foods to avoid for each blood type based on lectin reactions.
Scientifically Refuted: A comprehensive 2013 review found no evidence to support the health benefits of the blood type diet.
For B-Negative: The diet suggests avoiding chicken, corn, buckwheat, lentils, peanuts, and tomatoes.
Positive Results Misattribution: Any health improvements on the diet are likely from healthier eating habits in general, not blood type compatibility.
Lectins Not a Major Issue: Most lectins in foods are neutralized by cooking, and the theory of blood-type-specific reactions is unfounded.
Consider Evidence-Based Nutrition: It is safer and more effective to follow widely accepted dietary guidelines than a restrictive, unproven diet based on blood type.

Understanding the Blood Type Diet Controversy

The Blood Type Diet, created by naturopathic practitioner Peter D'Adamo, is a dietary plan based on the theory that individuals with different blood types (A, B, AB, and O) should eat different foods to achieve optimal health. According to the theory, certain food proteins called lectins can react with a person's blood type antigens, causing potential health issues. However, a significant body of research, including a major systematic review in the American Journal of Clinical Nutrition, has concluded there is no scientific evidence to support the diet's claims. Many health professionals consider it a fad diet, pointing out that any health benefits likely come from eliminating unhealthy processed foods, not from tailoring a diet to one's blood type. Despite the scientific consensus, followers of the diet adhere to its specific guidelines, particularly regarding the foods to avoid.

Foods Recommended for B Negative People to Avoid

For individuals with Type B blood (including B negative), the diet suggests a number of foods to eliminate or reduce consumption of. These recommendations are based on the theory that specific lectins in these foods can be harmful. It's crucial to understand that this is the diet's perspective, which lacks mainstream scientific support. The list of foods to avoid is extensive, but the most commonly cited include:

Chicken: Despite being a lean protein, the diet claims chicken contains a lectin that can agglutinate Type B blood cells, potentially leading to immune and circulatory issues.
Corn: Both wheat and corn are often mentioned as having lectins that can affect the metabolic efficiency of Type B individuals, causing fatigue and weight gain.
Buckwheat: This seed is another item the diet suggests avoiding due to its purported negative impact on metabolism and blood sugar regulation.
Lentils: Various beans and legumes, including lentils, are considered problematic for Type B individuals by the diet's proponents, with claims that they interfere with metabolic processes.
Peanuts and Sesame Seeds: The diet advises against consuming these, citing their lectins as a potential issue for the metabolic system and overall health.
Tomatoes: This common vegetable is also on the list of exclusions, with the diet suggesting it can irritate the stomach lining of Type B people.
Pork: Meats like pork, bacon, and ham are discouraged for Type B individuals.
Certain Oils: The diet suggests avoiding oils like corn, sunflower, and sesame oil in favor of alternatives like olive oil.

A Comparison of Blood Type B Diet Recommendations


Food Category	Recommended (According to BTD)	Avoid (According to BTD)
Meats	Lamb, Mutton, Rabbit, Venison	Chicken, Pork, Bacon, Ham
Dairy	Kefir, Yogurt, Feta, Goat Cheese	American Cheese, Blue Cheese, Ice Cream
Grains	Rice, Millet, Spelt, Oat Bran	Wheat, Corn, Buckwheat, Barley
Legumes	Navy Beans, Kidney Beans, Lima Beans	Lentils, Black-eyed Peas, Garbanzo Beans
Nuts & Seeds	Walnuts, Chestnuts, Almonds	Peanuts, Sesame Seeds, Cashews, Pistachios
Vegetables	Green Vegetables (Kale, Broccoli), Carrots, Eggplant	Corn, Tomatoes, Olives, Pumpkin

Why the Scientific Community Disagrees

Several studies and reviews have found no scientific basis for the blood type diet. In 2013, a systematic review of 1,415 scientific articles on the blood type diet found no evidence to support its claims. Another study involving 1,455 participants found that while following a plant-based diet improved some health markers, it did so regardless of the participant's blood type. This indicates that any benefits experienced on the diet are likely due to healthier food choices in general, such as replacing processed foods with whole foods, and have no connection to a person's blood type.

Furthermore, the theory regarding lectins is largely exaggerated. While some raw legumes do contain lectins that can be harmful, cooking typically neutralizes them. The idea that specific lectins react uniquely with certain blood types is not supported by mainstream science.

Considering a Healthy Alternative

Instead of focusing on scientifically unfounded restrictions based on blood type, a more reliable approach is to follow widely accepted nutritional guidelines. A balanced diet rich in fruits, vegetables, whole grains, and lean proteins is beneficial for everyone, regardless of blood type. If you are considering a significant dietary change, it is always best to consult with a doctor or a registered dietitian. They can provide personalized, evidence-based advice that accounts for your unique health needs, rather than a one-size-fits-all approach based on an unproven theory.

Conclusion

While the Blood Type Diet suggests a list of foods that blood type B negative people should avoid, these recommendations are based on a theory that has been widely refuted by the scientific and medical communities. The potential health benefits of following the diet are not related to blood type but rather to the overall healthier food choices it encourages. By focusing on a balanced, nutrient-dense diet and consulting with healthcare professionals, individuals can achieve better health outcomes based on credible, evidence-based nutrition.

Disclaimer: The information in this article is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making any significant changes to your diet.

Frequently Asked Questions

The scientific community largely agrees that the Blood Type Diet is not supported by evidence and lacks scientific validity. A 2013 review found no studies confirming the diet's benefits, and multiple health experts have debunked its central claims.

No, the Rh factor (positive or negative) does not affect dietary needs. The Blood Type Diet focuses on the ABO blood type antigens (A, B, AB, or O), and the Rh factor is not part of its theoretical framework or food recommendations.

According to the Blood Type Diet, chicken should be avoided by Type B individuals. However, there is no scientific evidence to support this claim. Chicken is a lean protein source, and avoiding it without a scientific reason could potentially restrict a healthy food group.

The diet claims that lectins in wheat and corn can negatively impact the metabolism of Type B individuals. Mainstream science has refuted this, suggesting that the lectin theory is overblown and that these food restrictions lack evidence.

Any health improvements likely stem from adopting healthier eating habits, such as consuming more fruits and vegetables and fewer processed foods, rather than following the blood type restrictions. The placebo effect can also contribute to perceived benefits.

While not inherently dangerous for all, the diet's restrictive nature can lead to nutritional imbalances or unnecessary avoidance of healthy foods. The Type B diet, for instance, is higher in saturated fat from certain dairy and meat, which could increase heart disease risk if not managed.

A superior alternative is to focus on a balanced, varied diet based on established nutritional science, including fruits, vegetables, whole grains, and lean proteins. Consulting with a healthcare provider or a registered dietitian is the best way to get personalized dietary advice.