The Controversial Blood Type Diet for B+ Individuals
First popularized by Dr. Peter D'Adamo in his 1996 book, Eat Right 4 Your Type, the blood type diet suggests that your nutritional needs are determined by your blood type. According to the theory, individuals with Type B blood are believed to have evolved from nomadic tribes with a varied diet of animal and plant foods. The diet's core principle revolves around proteins called lectins, which D'Adamo claims can interact negatively with a person's blood type antigens, causing issues like inflammation and metabolic problems. For those with a B+ blood type, this results in a list of foods to enjoy and a specific list to avoid.
The Blood Type Diet's List of Foods to Avoid for B+
Based on the blood type diet theory, certain foods are considered 'harmful' or 'avoid' for B+ individuals due to their supposed lectin content and effect on metabolism. These foods are claimed to cause weight gain, fluid retention, and fatigue, among other issues.
Grains and Starches:
- Wheat products (whole-wheat bread, flour, wheat germ)
- Corn (cornmeal, cornflakes)
- Buckwheat and products made with it
- Rye
- Wild rice
Legumes, Nuts, and Seeds:
- Lentils
- Peanuts and peanut butter
- Sesame seeds and sesame butter (tahini)
- Black-eyed peas
- Pumpkin and sunflower seeds
Poultry and Seafood:
- Chicken (especially disliked in the diet)
- Duck, goose, quail
- Pork (bacon, ham)
- Shellfish (crab, shrimp, mussels, lobster)
Fruits and Vegetables:
- Tomatoes
- Avocados
- Coconuts and coconut products
- Olives
- Artichokes, radishes, pumpkin
Beverages and Condiments:
- Carbonated beverages
- Certain oils (corn, canola, sunflower, sesame oil)
- Ketchup
The Scientific Rebuttal: Evidence vs. Theory
Despite the specific recommendations, a wealth of scientific literature contradicts the core claims of the blood type diet. In fact, a systematic review published in 2013 found no evidence to support the effectiveness of blood type diets. A subsequent 2014 study found no association between following the diet and improved cardiometabolic risk factors. Health experts, including registered dietitians, widely dismiss the diet as a fad.
Many of the suggested food restrictions are not based on sound nutritional science. For instance, the premise that lectins from certain foods cause harm is largely debunked; most lectins are deactivated by cooking and processing, making them safe for consumption. Any observed health benefits from following the diet are more likely a result of removing processed junk food and focusing on whole foods, a general principle of good nutrition, rather than the blood-type-specific rules.
Blood Type Diet vs. Evidence-Based Nutrition
This table highlights the differences between the Blood Type Diet's restrictive claims for B+ individuals and recommendations based on scientific, evidence-based nutrition principles.
| Food Group | Blood Type Diet Claim | Scientific Nutritional Advice |
|---|---|---|
| Grains | Avoids wheat, corn, and buckwheat; favors rice and spelt. | Whole grains (including whole wheat and corn) are important for fiber, vitamins, and minerals. The focus should be on variety and moderation. |
| Protein | Avoids chicken, pork, and shellfish due to supposed lectin effects. | Lean protein sources like chicken, fish, and legumes are a cornerstone of a healthy diet. Avoidance is unnecessary unless there is a genuine allergy. |
| Vegetables | Avoids tomatoes, corn, and specific varieties of olives and artichokes. | All vegetables, including those on the 'avoid' list, provide essential nutrients and should be part of a balanced diet. |
| Legumes | Avoids lentils, peanuts, and some beans. | Legumes and nuts are excellent sources of plant-based protein, fiber, and healthy fats for most people. |
| Dairy | Encourages most dairy products but restricts specific cheeses. | Dairy consumption is based on individual tolerance (e.g., lactose intolerance) and general health goals, not blood type. |
Conclusion: Prioritizing Evidence-Based Nutrition
When considering what foods should B+ blood type avoid, the answer from mainstream science is that no foods should be avoided purely based on blood type. While the Blood Type Diet may encourage healthier eating by cutting out processed items, its specific restrictions are not backed by scientific evidence. For truly personalized and effective nutrition advice, focus on your individual health needs, dietary preferences, and any specific health conditions you may have. Before making any significant dietary changes, it is always recommended to consult with a registered dietitian or other healthcare professional. You can read more about the scientific debunking of the Blood Type Diet on sources like WebMD.
