The theory that you should eat certain foods based on your blood type was popularized in a book by naturopath Peter D'Adamo called "Eat Right 4 Your Type." He argues that blood type helps to dictate how your body digests food, and he says certain foods are more likely to cause health and weight problems among people with different blood types. The diet plan has drawn criticism from health professionals who cite a lack of independent scientific research to back the theories.
Ancestors
D'Adamo's theory stems from research he conducted into genetics, anthropology and medical history. He says blood type O was the first to develop during the ancient hunter-gatherer period. Therefore, he argues that today's Type O's do best when they eat like their early forebears and thrive on meats and other high-protein foods. Type A's, on the other hand, trace their roots to ancestors who lead a more agrarian lifestyle and do best on a diet heavy on vegetarian fare.
Medical Theory
Proponents of blood-type diets say they work because food proteins called lectins are digested in different ways among people of various blood types. The theory is that choosing foods that work best with your blood type will not only help you lose weight, it will also help you feel better and avoid certain medical conditions. D'Adamo says it's your type of blood, not your Rh factor, that matters most. Therefore, his diet plan makes no major distinction between people with O-positive and O-negative blood.
Type O Foods
The list of foods for Type O's on the Blood Type Diet is heavy with protein-rich items and short on carbohydrates. D'Adamo recommends people with type-O blood consume meats, poultry, fish and olive oil. Many fruits and vegetables are good to eat, but some vegetables, such as beans, cabbage and potatoes, should be avoided. Other foods to avoid include grains and dairy products. D'Adamo says wheat gluten is a primary cause of weight gain in Type O's. Processed foods should also be avoided.
Exercise
D'Adamo argues people should not only choose foods by blood type, they should also choose their exercise. According to his theory, people with type-O blood need to get intense physical exercise, much like their hunter-gatherer ancestors. He recommends Type O's team the Blood Type Diet with a regular exercise regime that includes aerobic-type workouts three of four times a week. D'Adamo says Type O's thrive on active sports, such as running and martial arts.
Warnings
Nutritionists warn that diet plans that eliminate whole food groups may cause people to suffer from a lack of vital vitamins and minerals that come from those food groups. D'Adamo recommends supplements for each blood type, but federal health officials say most people should be able to get all the nutrients they need from the foods they eat.
References
- Eat Right For Your Type
- Every Diet: Blood Type Diet
- MayoClinic.com: What Is the Blood Type Diet?; Katherine Zeratsky; August 2010
- The Doctors of USC: The Blood Type Diet; Maria Adams; December 2009
- Vanderbilt University Psychology Department: Eat Right 4 Your Type; Courtney Sanders
- Centers for Disease Control and Prevention: Healthy Weight---It's Not a Diet, It's a Lifestyle!
