The Eat Right for Your Blood Type Diet

What It Is

The Eat Right for Your Type diet encourages people to eat certain foods and avoid others based on their blood type — A, B, AB, or O.

Peter J. D’Adamo, ND, the author of Eat Right for Your Type: The Individualized Diet Solution to Staying Healthy, Living Longer & Achieving Your Ideal Weight, believes blood types affect the digestive system and that some foods good for people of one type are “dangerous” for another.

It goes further than that for D’Adamo, a naturopathic doctor, who believes that your blood type also determines your susceptibility to certain illnesses and how you should exercise.

Critics cite a lack of published evidence backing D’Adamo’s blood type-based diet plan. “I know of no plausible rationale behind the diet,” says John Foreyt, PhD, a researcher at the Baylor College of Medicine in Houston.

This diet may suit those enthusiastic about a plan that doesn’t involve tracking calories or fat grams, while others may find it difficult to stay within the diet’s confines, a challenge made greater if more than one person in a household follows the diet — and has a different blood type.

What You Can Eat on This Diet

What you can eat — and how you exercise — on this diet depends on who you are.

If you’re blood type O (“for old,” as in humanity’s oldest blood line) your digestive tract retains the memory of ancient times, says D’Adamo, so you’re metabolism will benefit from lean meats, poultry, and fish. You’re advised to restrict grains, breads, and legumes, and to enjoy vigorous exercise.

Type A (“for agrarian”) flourishes on vegetarian diets, “the inheritance of their more settled and less warlike farmer ancestors,” says D’Adamo. The type A diet contains soy proteins, grains, and organic vegetables and encourages gentle exercise.

The nomadic blood type B has a tolerant digestive system and can enjoy low-fat dairy, meat, and produce but, among other things, should avoid wheat, corn, and lentils, D’Adamo says. If you’re type B, it’s recommended you exercise moderately.

The “modern” blood type AB has a sensitive digestive tract and should avoid chicken, beef, and pork but enjoy seafood, tofu, dairy, and most produce. The fitness regimen for ABs is calming exercises.

How the Diet Works

D’Adamo rejects the idea that one diet fits all. With four unique blood types, why shouldn’t we have four specialized diet plans, he asks.

The right diet for your blood type comes down to lectins, food proteins each blood type digests differently, D’Adamo maintains.

If you eat foods containing lectins incompatible with your blood type, he says, you may experience inflammation, bloating, a slower metabolism, even diseases such as cancer. The best way to avoid these effects is to eat foods meant for your blood type.

ALL foods fall into 3 categories on the Eat Right for Your Type diet:

• Highly beneficial
• Neutral
• Avoid

Beneficial foods for your blood type act like medicine, neutral foods like food, while avoid foods “act like a poison,” says D’Adamo.

For example, type Os should steer clear of whole wheat and wheat germ because “eating gluten is like putting the wrong kind of octane in your car … it clogs the works,” D’Adamo says.

What the Diet Experts Say

“Within the diet itself are generally good diet recommendations,” says David W. Grotto, RD, LD, a spokesman for the American Dietetic Association. “D’Adamo doesn’t say avoid vegetables and fruit, for example — but his specific recommendations based on blood type — the science is not there to support it. I’m not aware that anyone has duplicated his research.”

The presumption that each blood types will thrive on certain foods but not others also gives Grotto pause. “I’m type O and apparently I should be feasting over roadkill. Well, that doesn’t work for me because I don’t like too much meat.”

Overall Grotto does not recommend the diet, believing it pigeonholes people into dietary restrictions without taking into consideration individual needs and tastes.

Critics also refute D’Adamo’s theory that there’s a connection between certain blood types and specific diseases. Though the theory has been long been investigated, no conclusions have been reached, says Andrea Wiley, PhD, an associate professor of anthropology at James Madison University in Harrisonburg, Va.

Food for Thought

As for why so many have embraced the Eat Right for Your Type diet, Wiley has a theory: “Dieting is one of those things people feel desperate about. … The blood-type diet sounds more scientific [than some others].”

But it’s the very lack of a solid scientific background that rankles most experts.

“If this diet wasn’t coming from the whole blood-type approach, I could recommend this,” says Grotto, “but the philosophy of blood type is very obscure and lacking in science.”

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