The blood type diet, popularized by Dr. Peter D'Adamo in his 1996 book "Eat Right 4 Your Type," suggests that your ABO blood group may determine the best foods for you to eat. The central theory revolves around the idea that different blood types react uniquely to lectins, proteins found in food, potentially causing agglutination (clumping) of red blood cells and increasing the risk of disease. This article delves into the specifics of the diet for individuals with O negative blood type, examining its principles, recommended foods, those to avoid, and the scientific evidence supporting or refuting its claims.
Core Principles of the Blood Type Diet
Dr. D’Adamo claims the optimal diet and exercise regimen for any one individual depends on their ABO blood type. He also claims that each blood type represents the genetic traits of our ancestors, such as which diet they evolved to thrive on. The blood type diet (BTD) categorizes foods to reflect the diet your ancestors would have consumed. Type O, known as Hunter, is supposedly the oldest blood type and thrives on a high animal protein diet.
According to the BTD theory, eating the wrong types of lectins may specifically target different ABO blood types. They may cause red blood cells to agglutinate, or clump together, which could increase your risk of disease.
Diet Recommendations for O Negative Blood Type
According to Dr. D’Adamo’s BTD, all four blood types can eat meat. However, the recommended diet for type A is mostly vegetarian and only recommends poultry and fish, while the type O diet is mostly animal protein-based. The Eat Right 4 Your Type program suggests that if you are type O, you stay away from wheat, dairy, caffeine, and alcohol. Reach instead for fruits, vegetables, and lean, organic meats. Those with type O blood should choose high-protein foods and eat lots of meat, vegetables, fish, and fruit but limit grains, beans, and legumes.
Foods to Embrace
The O blood type diet emphasizes a high-protein intake, mirroring the presumed diet of early hunter-gatherers.
Read also: Understanding the Type O Negative Diet
- Animal Proteins: The diet plan dictates that people in the O blood group should consume “beneficial” animal products, including beef, lamb, mutton, veal, venison, cod, herring, and mackerel. People with type O blood following the diet are allowed to consume most meat products, including cold-water fish. Supporters of the diet suggest that people with type O blood may experience unwanted weight gain when they eat particular food groups, such as dairy.
- Vegetables: With a few exceptions, people with type O blood can eat most vegetables, including tomatoes, artichoke, chicory, dandelion, garlic, horseradish, kale, okra, onions, parsley, parsnips, red peppers, sweet potatoes, pumpkin, seaweed, and turnips. All vegetables are ok, but choose broccoli, spinach, kale, and cos over cabbages, shitake mushrooms, eggplants, and potatoes.
- Fruits: Some of the recommended fruits for people with type O blood include plums, prunes, figs, grapefruit, and most berries. As for fruits, choose berries, persimmons, and plums.
- Nuts and Seeds: Nuts are a great source of protein and healthful fats, and people following the diet can typically have most nuts, except for the ones in the “foods to avoid” list below. Suitable nuts and seeds, including walnuts, hazelnuts, and almonds, are available to purchase online. Pumpkin seeds and walnuts supposedly provide the most benefits.
- Beans: People with type O blood tolerate beans. Proponents of the diet believe that the most beneficial beans for these individuals are adzuki beans, pinto beans, and black eyed peas.
- Grains: While most people on the O positive and negative diet should avoid grains, a few can remain in the diet, including amaranth, buckwheat, rice, kamut, kasha, and millet. Some people may also be able to eat gluten-containing grains, while others will be unable to tolerate them. These grains include barley, rye, spelt, and oat Essene bread and Ezekiel bread.
- Spices and Condiments: Spices that people following the diet can enjoy include kelp-based seasoning, iodized salt, parsley, curry, cayenne pepper, chocolate, cocoa, and honey.
- Beverages: People following an O positive and negative diet can drink the following: seltzer water, club soda, sparkling water, tea, and wine.
Foods to Restrict or Avoid
The O negative blood type diet also outlines foods to limit or eliminate.
- Animal Proteins: The diet plan for people with type O blood excludes pork, including ham and bacon, goose, barracuda, pickled herring, catfish, smoked salmon, caviar, octopus, and conch.
- Dairy: People following the diet should avoid dairy products not in the “foods to eat” list, including yogurt.
- Nuts and Seeds: Particular nuts also do not feature in the diet plan, including Brazil nuts, cashews, peanuts, pistachios, and poppy seeds.
- Beans: Beans that proponents of the diet advise against include copper beans, kidney beans, tamarind beans, and lentils, including domestic, green, and red lentils.
- Grains: The diet also excludes the following grains: corn, gluten, graham, bulgur, durum, sprouted, white and whole wheat, wheat germ and bran, farina, and seven grain.
- Vegetables: Although people in blood group O tolerate many vegetables well, the advice is that they should avoid vegetables belonging to the Brassica family, including cabbage, Brussels sprouts, cauliflower, and mustard greens, alfalfa sprouts, shiitake mushrooms, fermented olives, and vegetables from the nightshade family, including eggplant and potatoes corn leek.
- Fruits: People following the O positive and negative diet should also avoid several specific fruits: melons, including cantaloupe and honeydew, oranges, tangerines, strawberries and blackberries, rhubarb, avocado, and coconut and products that contain coconut.
- Spices and Condiments: Spices and condiments to avoid in the diet include pepper, both white and black, vinegar, capers, cornstarch and corn syrup, nutmeg, vanilla, ketchup, pickles, mayonnaise, and relish.
- Beverages: People with type O blood should avoid drinking the following, according to the diet plan: beer, coffee, distilled liquor, and black tea.
Scientific Evidence and Expert Opinions
While the blood type diet has gained popularity, scientific support for its claims remains limited. The minimal research that does exist on BTD doesn’t support Dr. D’Adamo’s claims that specific foods may cause benefits or harm to certain blood groups.
- Lack of Specificity: In a 2014 study of 1,455 participants, eating a type A diet of fruits and vegetables was associated with better health markers. However, this effect was seen in everyone following the type A diet, not just individuals with type A blood. Similarly, a 2018 study of 973 adults with overweight found that matching a participant’s blood type with the respective recommended BTD didn’t impact the link between BTD and markers of cardiometabolic disease. Lastly, in a 2020 study, 68 participants of different blood types ate a low fat vegan diet for 16 weeks. At the end of the 16 weeks, the researchers found no major differences in cardiometabolic changes between any of the groups.
- Agglutinating Lectins: Overall, however, it appears that the majority of agglutinating lectins react with all ABO blood types. This means that lectins in the diet may not be blood-type specific, except for a few varieties of raw legumes.
- Potential Benefits Unrelated to Blood Type: Some research suggests that eating certain foods is associated with better health markers. However, no research supports the claim that specific diets are better for specific blood types. The BTD removes the majority of unhealthy processed foods. This may be why it works, without any regard to the different blood types.
Liz Weinandy, RD, at the Ohio State University Wexner Medical Center in Columbus, Ohio, says that lectins can be dangerous to our health if eaten in large amounts, but the way D'Adamo presents their effects may be misleading. Reducing their potential health harms is relatively easy: For example, lectins found in dried beans can be eliminated simply by soaking the beans in water for a few hours and then boiling them for 10 minutes, Weinandy says.
Critics of the plan argue there is little to no science to back up the theory that eating according to blood type can improve your health.
Potential Benefits and Risks
The Eat Right 4 Your Type diet does help people reduce calories and can lead to weight loss. “Unlike a lot of other fad diets, the general advice is good,” Grotto says.
Read also: Weight Loss and Negative Calorie Foods
However, there’s concern that the Eat Right 4 Your Type diet for those with blood type O is too protein-heavy. “Animal protein, especially red meat, has been linked to health problems, such as heart disease and colorectal cancer,” says Grotto.
Also, dietitians say it’s possible that individuals may experience nutritional deficiencies when following the eating plan.
Sample Menu for Type O Blood
Here is a sample one-day diet for each blood type, based on D’Adamo’s recommended recipes: (6)Type OBreakfast Two slices of organic bread with almond butter, vegetable juice, and a bananaLunch A spinach salad with roast beef and fruit slicesSnack FruitDinner Lamb stew with a variety of vegetablesDessert Fruit salad
Read also: The Hoxsey Diet