According to Dr. Peter DÁdamo, author of Eat Right For Your Type, a chemical reaction occurs between your blood and the foods you eat. This reaction is part of your genetic inheritance. This reaction is caused by a factor called Lectins. Lectins, abundant and diverse proteins found in foods, have agglutinating properties that affect your blood. So when you eat a food containing protein lectins that are incompatible with your blood type antigen, the lectins target an organ or bodily system and begin to agglutinate blood cells in that area. The blood type diet is designed to target these specific factors.
Should you follow a specific diet and exercise plan based upon your blood type? That is what Dr. D’Adamo suggests in his book Eat Right for Your Blood Type. D’Adamo is a naturopathic doctor who feels that one’s blood type may determine which diseases and illnesses you may develop. It is an intriguing approach; however, no research has been conducted, and there are no studies that show blood type can be a predictor for the development of certain diseases.
That being said, if you are intrigued by the idea of eating according to your blood type, here is the basic premise of the diet: D’Adamo is that not everyone should follow the same diet, and that blood type and your race determines tolerance to what you should and should not eat. Based on this, there are 16 groups of food that are highly beneficial, neutral or should be avoided.
Blood Type O
For the majority of people, the prescribed diet is low-carbohydrate, high in proteins (such as meat and fish), and low in dairy products. Type O should also engage in lots of exercise.
Choose: Lean beef, chicken, fish, turkey, vegetables, and fruit.Limit: dairy, grains, legumes, and beans.
Some specific foods to avoid: avocado, brazil nuts, oranges, cauliflower, mustard greens, cabbage, brussels sprouts, pork, goose, poppy seeds, eggplant, corn, melons, coconut, coffee, beer, black tea, ketchup, vinegar, milk, yogurt.
Blood Type A
These people should eat eat plenty of fish and vegetables, with a low dairy intake. Light exercise only.
Limit: chicken, turkey, and dairy.
Some specific foods to avoid: beef, pork, shellfish, aged cheeses, cashews, pistachios, kidney and lima beans, wheat bran, potatoes, olives, yams, cabbage, mushrooms, tomatoes, melons, bananas, oranges, mayo, beer, black tea.
Blood Type B
People with type B should eat plenty of certain meats, dairy, some fish, and plenty of fruit and vegetables.
Limit: beef, turkey
Some specific foods to avoid: chicken, other poultry, pork, shellfish, American cheese, blue cheese, sesame, lentils, chic peas, black beans, wheat, corn, tomatoes, avocado, pumpkin, olives, coconut, pomegranates, pepper, ketchup, distilled liquor
Blood Type AB
This plan combines some aspects of both the A and B diets and has the most acceptable food choices for dieters.
Limit: No grey area with type AB
Some specific foods to avoid: beef, pork, poultry, venison, shellfish, aged cheeses, sesame, kidney, black, and lima beans, sunflower seeds, buckwheat, corn, avocado, bell peppers, black olives, tropical fruits, oranges, pepper, black tea, distilled liquor.
What do the experts say?
Medical experts universally agree that the theory is nonsense, and say there is absolutely no link between our blood group and the diet we eat. Consequently you won’t find qualified nutritionists or dietitians recommending this diet.
There are also several concerns, namely that the diets recommended for blood groups O and A are considerably limited and cut out major groups of foods.
In the long term, this can result in a poor intake of nutrients needed for good health. Cutting out dairy products, for example, will lead to poor intakes of calcium, which can put you at risk of osteoporosis (brittle bone disease), while avoiding meat can result in low intakes of iron, which can lead to anaemia. This is even more worrying in view of the fact that most people in the UK are blood group O or A.
But will the diet help me lose weight?
Almost certainly, but this is because each of the diets for the four blood types eliminates specific groups of food such as bread and cereals, dairy products or meat and fish. Dr D’Adamo doesn’t give any indication about how much weight you’ll lose, it will depend on how much you restrict your food intake.
Eat Right for Your Type: Pros
“I have no problems with the blood type A recommendations, which is a plant-based diet,” says Grotto. “Overall, the recommendations are good for most of the blood types.”
Also, the Eat Right for 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,” says Grotto. “I have dealt with patients who say they feel better after following the diet.”
Eat Right for Your Type: Cons
While the diet might help with weight loss, whether it has more significant health benefits is another matter entirely. Critics of the Eat Right for Your Type diet say that there is little to no science to back up the theory that eating according to blood type can improve your health.
“What do clumping blood cells have to do with weight? I can understand heart disease and risk for blood clots,” Grotto says. “[But] as far as I know, there is no science to support the connection of agglutination and obesity, cancer, and so on.”
There is also concern that the Eat Right for 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, who suggests eating no more than three servings of meat a week.
Yes, there is some evidence that people with certain blood types may develop certain illnesses. “Individuals with type O blood may be at greater risk for duodenal ulcer. Those who are type A may be at increased risk for atrophic gastritis,” says David J.A. Jenkins, MD, Canada Research Chair in Nutrition and Metabolism at the University of Toronto. Some blood type O patients have specific proteins that are attacked by the bacteria Helicobacter pylori, commonly linked to ulcers. Similarly, that bacteria has also been associated with atropic gastritis, though the exact relationship between type A blood and atrophic gastritis is not known. However, there is no evidence to support the theory that eating a diet tailored to a certain blood type has any effect on these conditions, says Dr. Jenkins.