While some of the food lists in the diet give healthy options, the fact that so many nutritious foods are restricted is troubling.
The concept behind the blood-type diet is simple: Determine your blood type, follow the diet and exercise plan for that type, and voila, you'll lose weight, reduce your risk of chronic illness, such as cardiovascular disease and diabetes, avoid common viruses and infections and slow the aging process -- or so the diet claims. The Blood Type Diet contends that chemical reactions occur between your blood and the foods you eat -- eat the wrong food for your blood type and suffer adverse health consequences. So how do you know what foods to eat or avoid? To answer that question, the diet's author considers when your blood type first appeared in history. Type O, for instance, which is apparently the oldest blood type, emerged at a time when people had to hunt for their food to survive, thus the emphasis on meat in this diet. Type A's, on the other hand, were cultivators and ate more vegetarian foods. Type B's were nomads, eating the widest range of foods, while type AB's are called enigmas, for they combine types A and B, requiring meat but in smaller portions.
All four plans on the Blood Type Diet (for types O, A, B and AB) have different food requirements which are broken into three categories: highly beneficial (the food is like a medicine), neutral (the food can be enjoyed without positive or negative consequences) or avoid (the food acts like a poison).
Type O individuals, for instance, are encouraged to eat a diet high in animal protein (i.e. lean red meats and poultry) but limited in dairy products, grains (especially wheat) and legumes. Type A's, on the other hand, are advised to follow a vegetarian diet, consuming beans, legumes, cereals, vegetables, fruits and small amounts of dairy products but eliminating all meats. Meanwhile, the type B diet encourages meat (but not chicken), dairy products, all fruits, most vegetables, some beans, no nuts or seeds and no wheat. And those on the type AB diet are allowed to eat some meat, some dairy products, limited wheat products and most fruits and vegetables.
The diet was created by Peter J. D'Adamo, N.D., a naturopathic physician whose father first introduced him to the idea that optimal health might be linked to specific diet and exercise patterns for each blood type. D'Adamo continued exploring this theory and eventually concluded that his father's observations held merit, hence the birth of the Blood Type Diet. Although D'Adamo attempts to bring in scientific facts, this diet is based on convoluted nonsense. No studies, after all, indicate that your blood type should determine what you can or can't eat. Even worse, all four of these diets require you to abide by lists, shunning many foods that are otherwise healthy. And although these diets do recommend exercise, there's no logical rationale for creating an exercise program based solely on blood type.
Is the diet healthy?
Not necessarily. While some of the food lists in the diet give healthy options, the fact that so many nutritious foods are restricted is troubling. The list concept is also extremely structured, and this rigidity may doom many people who attempt this diet.
What do the experts say?
"There's no scientific proof that eating and exercising according to your blood type will help you lose weight," says Katherine Tallmadge, M.A., R.D., spokesperson for the American Dietetic Association. "If you follow the diet and do lose weight, it's probably because you're eating fewer calories, not because there's something magical going on with your blood type and the foods you're eating."
Who should consider this diet?
Nobody.
Bottom Line
Each of the four blood type diets is too restrictive, asking you to follow lists and cut otherwise healthy foods from your diets. As Tallmadge says, dividing foods into good and bad categories is simply not a healthy approach, for almost all foods can fit into a diet. And by cutting healthy foods, you'll miss out on valuable nutrients assuring your diet will be unbalanced and unenjoyable.
Checklist
Cost: Expensive. You may require a test to determine your blood type and will then need to follow specific recommendations for your blood type, some of which may include expensive food items like veal and mutton. Supplements are also advised for all blood types.
Meals Provided: No.
Diet Duration: It's suggested that you stick with this diet for a minimum of two weeks, but there's no maximum length.
Fitness Requirements: Yes. The activity is determined by your blood type. Type O's are required to do high-intensity aerobic exercise while yoga, tai chi and moderate-intensity aerobic activities are recommended for type A's. The type B exercise plan combines moderate-intensity activities like hiking with relaxation exercises while Type AB's are encouraged to do more calming activities.
Time Commitment: Depends on your blood type, as each of the four diets has different requirements for eating and exercising.
Eating Out: Yes, as long as you stick with the food for your blood type.
Alcohol: Possibly, depending on your blood type.
Vegetarian-Friendly: Only if you also happen to have type A blood.
