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3 Reasons To Avoid The Blood-Type Diet

3 Reasons To Avoid The Blood-Type Diet

For starters, it has no basis in science or reason. Learn how the fit-minded should eat instead.
Eat Right For Your Blood Type

Eat Right For Your Blood Type, a book by Dr. Peter J. D'Adamo, isn't a nutrition work for Twilight fans. The author's concept, simply put, is that everyone can and should follow an optimal diet according to whether their blood type is A, B, AB, or O.

It all sounds very scientific, doesn't it, in a nerd-glasses-and-lab-coat kind of way? You know there's some 23-year-old actress out there waiting to offer a gushing endorsement of this diet as the cure for everything that ails everyone on Earth.

Indeed, we're all born with a different set of genetics, which we know contributes to our risk for some diseases and other medical conditions. To eat in a manner that coincides with our genetic makeup, while improving our health? Makes perfect sense, right?

The problem is, unless you recoil from garlic and sleep in a coffin, the so-called blood-type diet kind of, well, sucks.

The good doctor believes that certain foods are good for your blood type, and that others are dangerous. Eat foods from the latter category, and you may experience a variety of health issues, ranging from inflammation and bloating to a slower metabolism and even diseases such as cancer. Or so the book says.

Blood Type Specifics

Here's how he breaks down the dietary specifics for each blood type:

O = "old" or ancient times

  • Is intolerant to dietary and environmental adaptations
  • Lean meats, poultry, fish
  • Restrict grains, legumes
  • Responds best to stress with vigorous exercise
  • Requires an efficient metabolism to stay lean and energetic

A = "agrarian"

  • Has a sensitive digestive tract
  • Vegetarian diet
  • Tolerant immune system
  • Adapts well to settled dietary and environmental conditions
  • Responds best to stress with calming actions and gentle exercise
  • Requires agrarian (based on agriculture) diet to stay lean and productive

B = "nomadic"

  • Has a tolerant digestive system
  • Can tolerate the most flexible dietary choices
  • Low-fat dairy, meat, produce
  • Avoid wheat, corn, lentils
  • Responds best to stress with creativity
  • Moderate exercise
  • Requires a balance between physical and mental activity to stay lean and sharp

AB = "modern"

  • Has a sensitive digestive tract
  • Avoid chicken, beef, pork
  • Should eat seafood, tofu, dairy, most produce
  • Responds best to stress spiritually, with physical verve and creative energy
  • AB is an evolutionary mystery
The good doctor believes that certain foods are good for your blood type, and that others are dangerous.

Eat Right For Your Blood Type gives you portions of the best foods listed for you. It also lists foods that encourage both weight gain and loss for each blood type. He also offers case examples, answers common questions, and addresses different situations that might arise (food allergies, diseases etc.) for each group.

Why This Diet Isn't For You

Unfortunately, the book raises more questions than it answers. I've singled out three reasons in particular why this diet isn't necessarily for you:

The diet is short on science

In the <i>Eat Right For Your Blood Type</i> diet, foods are portioned out differently based on your ethnicity
In the diet, foods are portioned out differently based on your ethnicity.

The recommendations made on are based on science and experience. The take-home:

  1. Eating small, healthy meals throughout the day will help control hunger and manage insulin levels, giving you a constant source of energy.

  2. Getting enough quality protein will ensure that you are building a lean-yet-muscular physique.

  3. Using the right supplements in the right doses at the right times will support your overall health and training program. Though Eat Right for Your Blood Type sounds scientific, it's anything but.

The diet isn't individualized

At first glance, Eat Right For Your Blood Type seems individualized-it zeros in on your blood type. However, it doesn't take into account your medical history, medications, current or target body weight, food likes and dislikes, food allergies or intolerances, diet history, and more. The ideal dietary approach for you should account for all of these factors.

The diet does, bizarrely, account for ethnicity

In the Eat Right For Your Blood Type diet, foods are portioned out differently based on your ethnicity. There's no rhyme or reason for doing this.

Though Eat Right For Your Blood Type isn't a harmful diet, it also isn't based on any science; therefore, there's no guarantee or even a suggestion that it will work for you. You'll be better off learning from the articles on and taking your own situation into account to create a plan that meets your specific needs.

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About The Author

Marie Spano, MS, RD, Vice President of the International Society of Sports Nutrition (ISSN) is a registered dietitian with a MS in Nutrition...

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I have to strongly disagree with this article. When I was in Maryland I went through a second ACL reconstruction surgery and I was struggling to lose weight. I wasn't able to workout as hard as I did in college because of my knees. I went and spoke to a doctor about my weight problems and she recommended the blood type diet by Dr. D'Adamo. She did some lab work and I had high blood pressure and my cholesterol was near bad. I stuck to the diet for a whole year before transferring to Virginia and within 4 months I lost 30 pounds of fat and gained 10 pounds of muscle. My cholesterol, blood pressure, labs and blood work were perfect.

The main problem people have with this diet is that they cannot fathom the idea of giving up eating things that they have been accustomed to ever since they were a kid

Feb 2, 2012 8:33pm | report

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It's good to see that I'm not the only one that has had success with this. It's not only about losing weight, it's about overall health and well-being in these books. And I agree with you brotha, the hardest part is cutting out those foods you've eaten your whole life and end up finding out they're bad for you.

May 12, 2012 8:59pm | report

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This article is garbage. I can attest to these "blood type" books. I am a type O. I've been eating clean and bodybuilding for almost 9 years. I always ate clean (low glycemic carbs at the right time, protein with every meal, etc.) And I could bulk up, but NEVER shred up. No matter what I did, I always had the puffy look. I was at 245 when I found this book and I was skeptical. For type O's it said to cut out wheat anything and gluten COMPLETELY because it is a form of poison to type O's. So the first week I stopped having oatmeal or whole wheat toast with my eggwhites in the morning. Lost 5 lbs in a week without counting calories or macronutrients. The next week I decided to add a few foods I didn't normally eat, but was advised as "highly benificial" from the book. Lost another 5 lbs in the next week. Within a month of cutting out several things that the book said to stay from, I was down from 245 to 220 RIPPED. And all of my exercises actually WENT UP in strength instead of went down like they normally would when you cut weight. I felt better, needed less sleep, good mood all day, and Finally saw my 6 pack abs I have not seen since I was 15. I stand by Dr. D'Adamo. It is the only thing that has EVER worked for me and believe me I've tried every diet strategy known to man. YOU CAN AND WILL HAVE SUCCESS WITH HIS BOOK. YOU CAN TAILOR THE BOOK TO YOUR BODYBUILDING NEEDS. JUST FOLLOW THE HIGHLY BENIFICIAL FOODS AND STAY AWAY FROM THE "AVOID" FOODS.

May 12, 2012 8:57pm | report

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This article is total bs, I have had similar results as the people who shared below, if you have a basic understanding or evolution or adaptation you can appreciate the science of the book, not to mention most wheat and dairy products aren't good for a majority of the population, not just o blood types

Aug 8, 2012 8:57pm | report

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Well i'm type A and there is no way i'm going to put any vegetables in my mouth exept for broccoli or potatoes. I'm always eating dairy products and meat and ofc all gind of grain stuff. Eating broccoli all day would kill me, eating anything else will make me puke (thats truth, i puke if i eat salad or some else vegetable).

Aug 18, 2012 1:25pm | report

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Type A here.

In my opinion, this article is dead on accurate.

I eat at LEAST one steak a day, not to mention TONS of potatoes, and a gallon of milk every 2-3 days tops (and pretty much everything else on their list), and I have none of the digestion issues listed for my blood type.

Hell, I'm on a ckd right now (so no potatoes or milk atm), and eating straight animal flesh, fat, and oil for every single meal I eat and feel great (aside from staying hungry!).

In short, this diet is a bunch of nonsense. There are way to many variables that come into play to just dump everything onto blood type. I see some posters claiming miracles for this diet, but if I was a betting man, I'd say their results came from actually planning out, tracking, and sticking with a diet.

In fact, one of the posters even gives it away in his reply by stating that he wasn't counting calories or macros.



Considering the way people like to demand scientific proof in regards to religion these days, you would think that they'd apply that same standard to things like diet as well, but quite obviously,...they don't

No offence to those of you that follow this diet, just calling it as I see it.

Aug 23, 2012 2:52am | report

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I never comment on this stuff but I signed up just so I could (maybe that was their plan). I understand more science is needed. I get people who are very active and young can seem to go against this and not pay for it. I get it, may not be true for all people. Plus you can 'train" your body to eat certain things depending on how you grew up. Get it.

But here is the thing. My wife, daughter, and I all have looked this over. Every last detail of this holds true for all of us. I'm B-. I feel slow and sluggish when I eat the 'bad' stuff. And feel great when I eat the other.

Cream of wheat for breakfast...I want to go back to bed.
Oats. Let's play tennis.
Tried to be 'Healthy' and eat only whole grain bread. Feel sick. Ezekiel bread, rice, no problems.

Milk. My body craves 1% milk. I could drink a gallon in one sitting. Can't stop. So I drink milk often as to not crave it insanely. Eat cottage cheese and blueberries as a near daily thing.

Ate lots of chicken throughout life, always felt 'heavy' after. Can eat gyro (lamb) and feel awesome. Guess what is on the B list?? Don't eat chicken, eat lamb.

One thing not true for my B type is olives. I can eat them no problems. Other than that, It holds true for me.

Sep 20, 2012 3:44pm | report

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I had to sign up to so that I could explicitly disagree with this article, because that's how strongly I feel about it.

I used to have hypoglycaemia, hypothyroidism and asthma. I used to eat high amounts of white potatoes, whole wheat breads, cereals, red meats and a much fewer number of vegetables as a young teenager into young adulthood, mixed with a high amount of physical activity. I did very well in all things physical but was struggling with low energy levels, constant tiredness, muscle fatigue and trouble taking in adequate amounts of oxygen during exercise.

I found the Blood Type Diet book from Dr. D'Adamo and it has literally changed me life. The only thing that I deliberately changed in my new lifestyle approach was my diet.

This is what it did for me.

I recently got blood work results back and it has been determined that after a year on this new Type O blood type diet, my hypothyroidism (which I was deigned to live with for the rest of my life) and hypoglycaemia have both mysteriously disappeared. My thyroid somehow reversed itself and functions normally now, without the aid of the medication doctors said I needed to take to avoid experiencing the ill-effects of an under-performing thyroid. My blood sugar levels are regulated and my energy and mood are predictable based upon what I eat. Since the type O diet encourages stopping the consumption of gluten, my body fat % has dropped from 16.9% to 9%. If I eat well according to the diet, I feel great. If I go off track, slice of whole wheat pizza with dairy cheese here, pint of wheat beer there, I feel terrible, and I notice the difference. It's like night and day the way I used to live to the way I live now. As well, my asthma has disappeared. Poof. Vanished. I now breath more deeply and clearly before, during and after exercise than I ever have in my entire life.

Thanks to Dr. D'Adamo and his blood type diet, I have ridded myself of the things that slowed me down the most. Some people may call it unscientific, and there will always be doubters, even registered dieticians. But there's nothing unscientific about my results.

Try it out and see how you feel; you might even surprise yourself.

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Nov 25, 2012 7:30pm | report

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nice info,am an A so I need to be a Vegan :(

Jan 5, 2013 9:47pm | report

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nice article,I'll try to be a vegan now :(

Jan 5, 2013 10:54pm | report

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I think this article is a load of crap. Check the's from 2011. Way more research time has been put into this diet. I personally have been on it since August 2012 and have seen nothin but results. I was ultimate carnivore til I did my research and started on this diet. I don't even crave meats like beef or pork anymore and feel 1000 times better (A blood type). Do your research like you're suppose to instead of believing the first thing you read.....especially when it says "look at our nutrition articles, they're way better"

Apr 3, 2013 10:50am | report

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They would print this because they'll lose money if people stop buying their supplements....It's all about the Benji's.

Sep 23, 2013 9:25pm | report

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I am an O type. and I have digestion and articulation problem. I found blood type diet. I found out that in my whole life I should eat what I didn't suppose to eat so now I get these health problems. for example tomato is not good for articulation or joint problems but I eat that Or when I ate wheat foods my digestion problem imminently starts. I'm so happy to find blood type diet and I want to start it now!!

Jul 31, 2014 6:36am | report
Showing 1 - 13 of 13 Comments

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