By Maureen Callahan, M.S., R.D
Updated: April 17, 2008

Continuing in the footsteps of his physician father, naturopath Peter J. DAdamo explores what he sees as a solid link between blood type and health. According to his theory, your blood type determines your susceptibility to disease, which foods you can tolerate, and what kinds of exercise are beneficial. When people eat the right foods for their blood type, DAdamo says, excess weight falls off—sometimes even faster than they might like. Its a matter of internal chemistry, as DAdamo explains in his book Eat Right for Your Type (G.P. Putnams Sons, 1996). Companion books include Allergies: Fight Them With the Blood Type Diet and Fatigue: Fight It With the Blood Type Diet (both, G.P. Putnams Sons, 2005).

Most health experts would agree with DAdamo that a “one size fits all” approach to dieting is wrong—but few would say that a plan based on blood type is the answer. In fact, theres no science to support the strategy. Chances are meat-loving Type AB dieters will see through the hocus-pocus pretty quickly since, according to the regimen, they should dine on tofu rather than steak. For others, the unique approach might sound promising at first, but chances are itll end up being a big headache.

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Basic principles:

There are four blood types: A, AB, B, and O. People with different types require different foods for optimal health. The diet isnt really about dropping pounds, but DAdamo claims that “weight loss is one of the natural side effects.” Dieters need to avoid foods that are toxic to, or promote weight gain for, their particular type. Recommendations for exercise also vary depending on blood type.

How the diet works:

Sixteen food groups (such as meats, dairy and eggs, grains, and spices) are divided into three categories: highly beneficial foods, neutral foods, and foods to avoid. The idea is to eat moderate portions from the beneficial and neutral lists and steer clear of items on the taboo list. For instance, Type Os should avoid ice cream, caviar, and (no kidding) barracuda. Type As must abstain from buttermilk, sherbet, and pistachios. Taboo for Type Bs are ketchup, corn syrup, and rhubarb. The no-nos for Type ABs: nearly every meat on the planet, including chicken, pork, veal, ground beef, and buffalo.

What you can eat:

Again, everything hinges on your blood type—no calorie counting, no measuring portions. Type O dieters fare well with high-protein meals that include lean organic meats (no more than 6 ounces per meal) and limited amounts of grains, legumes, and beans. Dairy, on the other hand, is poorly tolerated, and wheat products typically cause weight gain. Type As do best on a high-carb, low-fat vegetarian regimen. Type Bs can enjoy a varied diet, including dairy and grains. Get the picture?

Does the diet take and keep weight off?

No clinical data. DAdamo offers anecdotal evidence that the diet “works for 9 out of 10 people.” But its unclear if by “works” he means a drop in pounds or an improvement in overall health.

Is the diet healthy?

Debatable. Theres no concrete meal plan here to evaluate. Dieters will be choosing and avoiding foods based on lists. They could choose wisely, but they could just as easily choose poorly.

What do the experts say?

“We all have individual needs, but basing what you eat on blood type is ridiculous,” says registered dietitian Jane Kirby, author of Dieting for Dummies (Wiley, second edition, 2003). Edee Hogan, RD, a nutrition and culinary consultant in Washington, D.C., agrees: “Theres no indication that blood type has anything to do with anything other than blood type. Your basic nutrition needs are the same whether youre A-positive or B-negative.”

Who should consider the diet?


Bottom Line:

Don't bother.
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