#Health & Fitness

The Blood-Type Diet: A Genetic Key to Good Health?

by Allie Firestone

The Blood-Type Diet: A Genetic Key to Good Health?

It’s as easy as A, B, AB and O.


As someone who considers herself fairly nutrition- and health-savvy, I’ve read up on countless diet trends (and tried way too many of them). Naturally, my interest was piqued when I read about one new plan claiming that all of us possess a genetic trait that can put a stop to dieting frustration. This bit of genetic information will tell us what we should eat and how we should exercise for our healthiest and fittest bodies: our blood type.


According to Dr. Peter J. D’Adamo, a naturopathic physician and founder of this blood-based diet plan, breaking down people’s needs down by blood type explains the paradoxes that plague so many dietary studies. For example, how is it that my best friend always stays so trim, even though she eats carbs like she’s about to run a marathon, while others become bloated by merely touching a loaf of bread? I feel sluggish and heavy if I eat a lot of animal protein, while my boyfriend has some at just about every meal to keep his energy up.


Well, D’Adamo’s book Eat Right for Your Type: The Individualized Diet Solution to Staying Healthy, Living Longer & Achieving Your Ideal Weight states that looking to our blood type can explain these differences in diet and exercise needs. To find out whether his claims have merit, I decided to do some research of my own.


What Is the Blood Type Diet?
In his book, D’Adamo explains that knowingly using our blood type to guide our dietary and fitness decisions enables us to make more intelligent choices about our health. How? The diet plan breaks down the foods and exercises that we should incorporate and avoid to feel and look our best. According to D’Adamo, whether someone is an A, B, AB, or O blood type affects his or her digestive system, making certain foods good for some people and “dangerous” for others.


How can one diet plan be right for all of us? asks D’Adamo at the book’s opening. He has a point—how could my diet and exercise needs be the same as those of my next-door neighbor, my coworker, or someone who gets up and goes on a long run before work every morning?


D’Adamo explains that blood types affect how we digest food. Different blood types vary in how they’re able to break down food proteins, called lectins. Taking in lectins that don’t mesh well with our systems will leave us with a slower metabolism, bloating, and digestive irritation. Okay, we’ve all been there. But is it really explainable by blood type?


Breaking Down the Types
The diet plan splits foods into three categories: highly beneficial, neutral, and avoid. Foods in the beneficial category act like medicine, nourishing our bodies and flushing out toxins. Neutral foods can be paired with beneficial foods, while foods in the avoid category “act like poison.” Yikes. Have I been poisoning myself unknowingly all these years? The book and Web site break down very detailed and specific suggestions for everything from food to exercise and more that each type should strive to embrace—and avoid at all costs.


  • Type O: The O stands for old, as in humanity’s oldest bloodline. This means that these digestive systems fare best on an ancient human diet. These old-school humans benefit from eating animal proteins, like fish, poultry, and other lean meats, and from restricting grains, legumes, and dairy. O types should also aim for vigorous exercise on a regular basis, such as running, kickboxing, or intense hiking—think cavewoman hunting prey.
  • Type A: A is for agrarian. These gentler souls thrive on vegetarian-based diets since, according to D’Adamo, they’re descendents of less warlike, farmer ancestors. This means eating soy protein, organic fruits and veggies, and grains will leave type A’s feeling invigorated, as will gentle exercise, like yoga or walking.
  • Type B: This group needs to strive for balance. The nomadically inclined have more tolerant digestive systems, meaning they should enjoy meat and produce, as well as low-fat dairy. Foods to avoid include wheat, corn, and lentils. Exercise requirements include—you guessed it—physical and mental balance, like tennis, swimming, or cycling.
  • Type AB: People with this most modern (and rarest) of the blood types have sensitive digestive tracts, meaning they should avoid land animals (pork, beef, and chicken) and opt instead for protein from seafood, dairy, tofu, and produce. This type is a combination of A and B, so incorporating some of the A and B exercises will be effective.


The Verdict
Critics point to a lack of published scientific evidence backing the blood type–based diet. To that I say: fair point. Official literature on this diet cites survey information researchers have compiled on people sticking to the diet plan. An impressive 75 percent of respondents reported a success rate in improving their health conditions over time. But in terms of actual scientific evidence and backing, the theory has been investigated without resulting in any scientific conclusions, according to WebMD.


That said, the diet plan is grounded in solid health advice. Regardless of whether I decide to follow my actual blood type, or just the suggestions regarding the type that most appeals to my lifestyle, I’ll be eating a well-rounded diet and incorporating exercise on a regular basis—the chief ingredients for health and vitality. Lean meats, fresh produce, and regular exercise certainly don’t hurt—and that’s advice that’s been proven time and time again.