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Should I “eat right for my blood type?”

Robyn Openshaw - Jun 08, 2012 - This Post May Contain Affiliate Links

A recent grad from Institute for Integrative Nutrition applied for the GreenSmoothieGirl Health Coaches certification and said this:

“I’ve studied over 100 nutritional plans, and the 12 Steps to Whole Foods program is the most comprehensive, practical, grounded approach I have found.”

(That’s the goal. I think I’ve studied all those nutrition plans, too. Most have a kernel of truth, or lots of truth, along with, usually, some problems. And many of the diet plans appeal to popular tastes – such as Atkins, South Beach, The Zone, etc. — rather than being supported by evidence.)

One of the more frustrating diet plans, to me, is the blood type diet. The idea is that you have a certain blood type because your ancestors were from a certain place, so they adapted to a specific diet. You are then instructed, based on having O, A, B, or AB blood, to eat according to the prescription. Vegetarian, highly carnivorous, a mix of the two, grains or no grains, etc.

The diet has no real science backing it. Only a very dubious theory. The theory collapses when you consider that every indigenous population of the world has all the blood types: A, B, AB, and O. It’s also highly problematic when you consider how much genetic mixing and nomadism we’ve had in recent centuries. Few people have both parents going back to the same origins.

Peter D’Adamo fathered the first blood typing program (based on the theory of his father James, both naturopaths) that gave rise to a set of nutrition principles. But others have leveraged the same concept, with different recommendations. It’s tempting, financially, to author a new diet, since those books sell well. I know this all too well, since I waged an epic war with my publisher over the name of my bestseller, The Green Smoothies Diet. I hate the word diet because “diets” don’t work. I wanted to teach good principles, towards a sustainable lifestyle, but my publisher said,

“But American love diet books. They fly off the shelves.”

I lost the war and, in so doing, probably gained financially, as my book was instantly a bestseller for my publisher. It wasn’t a hill I was going to die on, because if it gets the same message out, I can “sell out” on the fairly minor point of a title. (Mostly, I just wanted, on principle, to name my own book!) And Ulysses Press was right—Americans do, apparently, want to “go on” yet another diet.

The whole idea of blood typing does call legitimate attention to the fact that we are all different, with different needs. This doesn’t obviate the fact that there are certain classes of foods that are nutritious to just about everyone. Just because you feel weak if you try to eat only plants, after a lifetime of eating animals, doesn’t mean that for you, vegetables are bad food.

It could mean you are transitioning and cleansing, and that is uncomfortable in the short- to mid-term. It could mean that because degenerative gut problems are nearly ubiquitous (everyone who has indulged in the S.A.D. suffering from them to one extent or another), many of us have developed sensitivities to specific foods. Some of those sensitivities are to good foods. This doesn’t mean that food X or Y is necessarily “bad” for you personally—it may mean that you have a problem to rectify so your body can accept and utilize nutrition from that food class.

Some people are reading this article and preparing to scream at me that I’m wrong because they went on the blood type diet and feel much better. I believe that! But not because you’re eating “correctly” for your blood type.

You feel better because the author of the nutrition program eliminates gluten from the type O diet. That will make everyone feel better, as grains have been hybridized and are causing many people problems. And he tells all type A’s to eat vegetarian, which is actually a good diet for most, if not all, people.

(As always, I refuse to take a stand on whether a limited amount of animal protein is good or desirable or at least acceptable—but it’s clear that more plants, and less animals, is across the board, more environmentally sustainable and more health-promoting.)

You feel better because regardless of your blood type, you’re told to eliminate processed foods such as white flour.

D’Adamo’s theory gets really silly when he tells Type A’s to meditate, Type O’s to do aerobics, etc. (Does this mean Type O’s shouldn’t meditate, and Type A’s shouldn’t exercise their hearts?) He delves into stereotyping personality and character based on blood type, too. It’s really nonsense but can “look” true because some true principles are involved.

Many other experts have soundly debunked D’Adamo’s reasoning and recommendations. He claims type O is the oldest blood type, but in fact, A is. This decimates the crux of his theory. Also, agriculture developed in different parts of the world independently, and his theory is based on unilateral development worldwide and positive outcomes for that development, neither of which is fact.

Most of his theory rests on lectins, proteins on the surfaces of foods that can cause cells or molecules to stick together. But a number of doctors object to the hypotheses the D’Adamos make, saying that there is no documentation of the health effects they predict if you eat “wrong” for your blood type, which virtually everyone does, of course. Michael Klaper, M.D. said that the effects he describes would be fatal for millions of people, if D’Adamo were correct in his theory.

The diets D’Adamo advocates for are not particularly harmful or out-of-the-ordinary, and all of them eliminate the worst of the bad in the Standard American Diet. (He isn’t telling any of the blood types to eat Twinkies or Cocoa Puffs. He is just making certain recommendations within whole-foods groups and macronutrients. Most Americans, of course, are eating Twinkies and Cocoa Puffs! Any  involves less processed food is likely to result in health improvement.)

As a culture, we need better critical thinking skills. We have a long love affair with personality testing and typing, horoscopes, and other ways to try to categorize and make sense of our world. But blood-typing theory is flawed on so many levels. I believe that individuals have specific dietary needs that may fall slightly – not massively — outside a prescribed set of guidelines.

Looking to blood type does not provide those answers. As logic might suggest to you, only experimentation and intuition do.

Posted in: 12 Steps To Whole Food, Whole Food

19 thoughts on “Should I “eat right for my blood type?””

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  1. Hey! I definitely don’t think that the blood type diet is any kind of miracle thing, but I believe in listening to your body, including your taste buds (with the exception there of very refined or sugary things). So as a type A, I was interested to realize that most of my favorite foods are listed as “highly beneficial” and the foods I dislike are listed as “avoid.” The same turned out to be true for my husband, a type B, and our daughters, a type O and a type A! That’s just too much for me to dismiss outright. So in closing, YES, intuitive eating, listen to your body!

  2. Anonymous says:

    My blood type is B+ and I found “most” of the foods I enjoy are considered No no’s /act more like a poison than a food. Disappointed so I ditched the whole theory and now listen to my body as well but after we were Robyn’s lucky winners of the 12 steps to whole foods we ditched meat/”most all dairy”…still working on this one and we feel great. I actually believed we would still be very hungry without a piece of meat of some sort on our plates until learning/practicing 12 steps. 12 steps has not only brought us closer together having fun in the kitchen with all these wonderful recipes but improving the way we both feel and helps on the grocery bill too. I can’t say enough about Robyn’s 12 step to whole foods and recommend this to everyone. I know our bodies are loving this new approach and I can’t wait to report back after living 12 steps in our home for the rest of the year. 🙂

  3. “there is food ye know not of…..”

  4. Anonymous says:

    Thanks. I had always wondered about the blood type diet- well before I even found out about green smoothies. So I am very grateful to have your well developed opinion on the matter.

  5. Anonymous says:

    quote: “… As a culture, we need better critical thinking skills. We have a long love affair with …” [various kinds of stupidity, mostly by indoctrination, which can use psychological or chemical technologies, etc.]

    From work back in the 70s with macrobiotics, I know that each of us can change our DNA and our bloodtype. By diet, I mean ALL the things we digest, including, from our foreheads to our eyes, ears, nostrils, and chins, our thoughts and prayers, the things we see, hear, smell, touch, and of course, the things or vibrations that we ingest, mechanically. All of the so-called “scientific dead-certainties” like DNA and blood type, are just momentary responses to environmental choices that we make. Can any principle of life, and the green smoothie just might be one (haha), grow out of a field that has been ploughed under with thousands upon thousands of scientifically indoctrinated “dead-certainties?”

    Those of us who find joy though evolution of consciousness find ourselves in a war. It’s always been that way. Our evolution of consciousness, which is somehow universal, is both individual and collective in nature. In that war, our most important power, and our most protective shield in that war, seems to be amplified in the dignity and courage of our men, and the innocence and moral strength of our women. Of course women have dignity and courage, and men have innocence and moral strength, but there is an emphasis. When men lost dignity and women and children lose innocence, there is a huge devolution in consciousness.

    This is way too huge a subject … start with, why are most of the heavy muscular organs of the body predominately on the left side … heart, stomach, duodenum, pancreas, spleen, descending colon … then left lung is larger (if volume of heart muscle is included), ;left kidney, left breast, left testicle is larger … why? then 70% of the immune system is on the left side (left side subclavicle lymphatic duct returns 70% of lymph flow …) why on the left side? The only organ compeltely on the right side is the tiny gall bladder … and all of its products are drawn over, as if by gravity, to the left … why?

    The beauty of the green smoothie, as an archetype, springs from the dignity, the purity, innocence and moral strength, of creating our own … out own evolution in consciousness. It cannot happen without sovereignty, and personal soverignty cannot happen with factory foods. The part of our diet what we intake through our mouths, is a small, but hugely important part. And, in this struggle for upward evolution in consciousness, our adversary (call it the factory, if you want), knows the chemistry and the technology of usurpation well.

    Rock on, Green Smoothie Girl!!!

  6. Anonymous says:

    I love your work Robyn, but I also love the Blood Type Diet, and feel great when I follow both. The only time I lose weight and feel great is when I follow the Blood Type Diet. It isn’t just because it eliminates gluten, although that is important for me. It also gives me a list of super foods in almost every category, that have helped me manage or bid farewell to a wide range of health problems: depression, panic attacks, arthritis, recurrent sinus and urinary tract infections, eczema, fatigue, hormone imbalances, autoimmune and inflammatory conditions, and h. Pylori. The diet is very focused of vegetables and fruit. For Os like me, it does recommend some lean, organic, free range meats, and they really improve my energy level and metabolism (I know a difference because I honestly don’t like meat and have sometimes avoided it). To say that it is not founded on science makes me wonder if you’ve read much of D’Adamo’s work. It is based more on DNA than loose theories on ancestral lines. For instance the genes are linked (neighbors that rarely split during mitosis) between intestinal alkaline phosphatase and blood type O. There is also a gene linked to the O gene that has to do with Monoamine Oxidase, which is important for mental health and also plays into diet and exercise recommendations. For more in depth reading about the science behind it, check out His publisher made him use the word Diet as well, and to write the books on a less scientific level, but the science is there, and it is helping many people with serious medical conditions. Thank you for taking a look.

  7. Anonymous says:

    i think that any diet that takes out the crap out of the diet is going to make you feel better. My friend works in an office where all the women are losing weight and feeling better but they are all on different diets. She is on the blood type diet. It works for her and her husband . I do not buy into it but it is helping her make healthy choices.

  8. Anonymous says:

    For many years I worked to improve my health with an acupuncturist (who is also a former RN) who was extremely skeptical of the blood type diet. However after hearing repeatedly of its benefits from colleagues at medical conferences she decided to explore it and see if it had any positive effects. To her surprise she found that the vast number of her patients benefited. Furthermore, she uses both live blood cell analysis and EDS (electro-dermal screening) to determine the best course of action for her patients, which includes the use of homeopathic and naturopathic supplements. She was able to actually see the changes in people’s blood based on their adopting the diet recommended for their blood type. Therefore, I think it is a mistake to dismiss the theory based on the formation of lectins just because some doctor(s) think it doesn’t hold up. Gut health is obviously essential to people’s overall health and foods that cause inflammation are best avoided. Ancient medical traditions such as ayurvedic and tibetan medicine clearly identify that people with the same conditions need to be treated differently according both to their constitutional natures and to the way the disease is manifesting. This takes into account the fact that the most beneficial diets are entirely different for different people. For instance, I tend toward being cold easily so it is best that I not eat foods that are cooling in effect, such as potatoes, bell peppers, raw tomatoes, eggplant, cucumbers, yams, turnips, unripe fruit, sugar or artificial sweeteners, cold liquids, chilled food, cooked food at room temperature, buffalo, pork or goat products. I have eaten green smoothies regularly at various times in my life and promoted them for many people. My husband eats them as a part of his lifestyle as a result of my encouragement. Right now they would exacerbate my health issues for reasons that are too complicated to go into here. I started exploring healthy eating back in 1970, became a vegetarian and began to make my own raw vegetable juices and grow sprouts, including wheat grass a few years later. So I have a great deal of experience. I also agree with the post above that suggests people should rely on their own intuition and experience, discovering how they feel after eating different foods.

    1. Robyn Openshaw says:

      Elinore and Melissa, I agree with you on virtually everything you’re saying here, including that some people need warming foods and that we all have idiosyncracies inside a basic need to eat healthy, whole plant foods (some people may even “need” to eat clean meat). I think almost EVERYONE would benefit on the blood type diet. It eliminates processed foods—all of the blood types’ diets do. And that’s why. Under heavy pressure, D’Adamo has stepped up the effort to show the “science” behind his theory. Many others (scientists and docs) very credibly dispute the “science” he uses. That said, if you love it, and if it adheres to good nutritional principles for you, go for it!

  9. Anonymous says:

    My hubby and I have type A blood and what is good for each of us is so very different. He needs lots of protein and I need a variety of things and I can eat loads of fruit and he can not.

  10. Anonymous says:

    Thank you for this article. My mom read that book about 10 years ago and will NOT get off that soapbox for anything. She still eats terribly and only followed that plan for awhile and yes she did lose weight and that was probably from taking out gluten and junk food. I believe she has been brain washed by that book as every single time I see her she brings it up as if it’s the Bible or something. She has nearly alienated all of her adult kids due to this book. It would be one thing if she stuck with it and actually lived the principals, but alas she couldn’t or didn’t but she still harps on it to everyone, and we are sick of hearing it!

  11. I get so frustrated by the blood type diet too. You mentioned that nomads and every other indigenous creature has had the same blood types. Exactly. Part of the blood type diets false advertising is this idea that blood types are a genetic mutation, that they didn’t come about until we discovered them. That’s such a silly concept to me. Bottom line, while nutrition can be a heavily debated topic, there are some universally accepted principles we can base our lifestyles on. Nutritionists will tell you that all man kind has certain basic essential nutrients. If you don’t get the nutrients you don’t get healthy. The blood type diet encourages certain cancer causing diets for some people and discourages certain essential nutrients for many. While we’re all biochemically different, that doesn’t mean we need dramatically different foods. Essential Nutrients are the same for all of us. We’re only biochemically different because our lifestyle’s are so different. Eating the same healthy foods would be part of that step toward having similarly healthy biochemistry. Other factors would include, exercise, happiness, rest, peace, and posture to name a few.

    1. Robyn Openshaw says:

      Ryan, that’s EXACTLY how I feel about it. Everybody wants to talk about individual health needs….and while there’s a kernel of that that MUST be addressed, certain nutrients are needed by everybody. EVERYBODY. And yes, some of the blood type diets promote cancer! D’Adamo’s theory came out long before the China Study and a lot of other data showing how high our risk of cancer is if we eat a lot of animal protein. BTW my staff hasn’t heard back from you about the coaching opportunity!

  12. Anonymous says:

    Hi, could I drink ormus supergreen and green smoothie per day? too much?

    1. Robyn Openshaw says:

      Yvonne, yes, I do both EVERY day. But if you’re coming off the S.A.D., it may be too much for your body all at once? Ramp up your greens gradually if you find you have a ‘detox’ reaction that is intolerable for you.

  13. Thankyou Robyn! As a nurse and naturopath, I have spent my entire adult life studying everything I could, and eliminating the rubbish from what is effective. One of my regular skills updates included a lecture on the blood group diet and people were oohing and aahing as this very cute, well proportioned girl told us about it, with the usual case studies supporting the D’Adamo theories. Of course, as my logical and skeptical brain always does (even when I don’t want it to…) I was already picking holes long before she finished. I added some of it to my repertoire which was always chopping and changing – long term vegetarian and sometime vegan (since about 9 years old) I managed to squeeze a little of it in between the food combining theories and zone theories – and out the other end came a mish mash of what we should and should not eat.

    Yet none of it in fact supported anything these experts had to say – like you said, the only common denominator is that processed foods, sugars, wheat, dairy and meat were questioned – and if removed, every follower will improve in health; a little like a very sick person who takes the most substandard multivitamin will improve – simply because it is a small improvement on what they had before.

    Like the SAD the Australian equivalent is atrocious but our doctors still say it is part of a well balanced diet and that even fast food fits in well. Over time I could see I would have no choice but to be harsh and very critical as my patients succumbed to sicknesses they should not have – if they were doing as I told them..

    As an O type there was no way on God’s green earth that I was going to eat meat – but I was told adamantly by a pro-blood type expert that is why I was still aging when I should not be. I have to admit it did scare me – 48 years old and despite a pristine, toxic chemical free, organic lifestyle I was still going down the slow hill.

    And then, in the back of my mind I remembered something I had studied years ago – in food combining – that little thing called alkalinity. D’oh! Man, was I so acidic! Those VERY few wrong things – like forgoing avocados because D’Adamo said so, still having occasional dairy (again…) – the recovery hit me like a tidal wave.

    Even my beautiful son in law, who was overseas dying of TB, miraculously cured by the alkaline diet – he had no access to smoothies so my daughter did all she could to ensure he got alkaline. It is no coincidence that 3 weeks after she had to return to Australia (alone) he died of simple gastric upset. His diet had reverted out of basic necessity (financial and geographical). And my daughter, bedridden for 3 years despite my knowledge, now vitally healthy just from the raw food, smoothie and alkaline diet. Prior to that, all my efforts were only temporary at best.

    I can’t tell you how many arguments I’ve had with colleagues over this silly diet – for one, unless you are atheist, it doesn’t make any historical sense anyway. And like you said, in my family alone, we have A, B, AB and O blood – so does that mean we all come from different blood lines?

    Thankyou for your work – it constantly verifies my own and I happily share it with my patients and health network. Keep it up!

    1. Robyn Openshaw says:

      Lulu, insightful and important post you’ve written here. WOW that you have four blood types in your family. That all by itself debunks the theory! I’m heartbroken about your son-in-law……God bless,

  14. Anonymous says:

    I am so glad to hear you pitched against the word Diet in your title! I almost did not buy your book because of it. That word has lost true meaning. If you publish another book I will back you up 100% percent on deleting that word from the title and usage in the book. I like the word lifestyle.

  15. Anonymous says:

    Your last line in the statement, “only experimentation and intuition do” !

    I have tried the blood type diet and am not afraid to say the WORD diet.

    It is great. Just because one type can handle eating more meat doesn’t mean there are hundereds of other non-meat options for that type. I feel so good when I follow my type.

    You are making a mistake to talk it down when you haven’t really understood it. You’re just rationalizing your conclusions.

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