Does the Blood Type Diet Really Work?

Written by Dr. Steve Chaney on . Posted in Food and Health, Issues

Is Eating Right For Your Blood Type A Sham?

Author: Dr. Stephen Chaney

cb43e76f-6bf7-4e82-8fc1-95005d2c5626Does the Blood Type Diet really work? In 1997 Dr. Peter J. D’Adamo wrote a book about the blood type diet called “Eat Right 4 Your Type”. Dr. D’Adamo claims that people with different blood types process food differently, so their blood type determines the type of diet that is healthiest for them. Specifically, he claims that people with:

  • Blood group O are descended from hunters and should consume high protein diets.
  • Blood group A are descended from farmers and should consume a near vegetarian diet – completely avoiding red meats.
  • Blood group B are descended from nomads. They have the most flexible digestive system and can eat the widest variety of foods – even dairy products, which he does not recommend for any of the other blood types.
  • Blood group AB are an enigma and are somewhere between blood group A and blood group B.

It’s an interesting concept. Dietary recommendations are made for populations as a whole, and there is tremendous genetic variation in populations. Because of that genetic variation, there is no perfect diet for everyone. Every knowledgeable health expert will tell you that.

The question then becomes “How do you know what kind of diet is healthiest for you?”

The blood type diet is a very simple system. Your blood type is easy to determine. Once you know your blood type you know what to eat. There’s no guesswork.

Could it really be so simple? Over 7 million copies of Dr. D’Adamo’s book have been sold. Millions of people believe in this concept. So it is only fitting to ask “What is the evidence?”

An Objective Scientific Analysis of the Blood Type Diet

There is no doubt that blood type is related to some human genetic and physical traits, but the important question is whether blood type is related to the health outcomes of different diets – the central thesis of Dr. D’Adamo’s book. A Belgian group lead by Dr. Emmey De Buch did a systematic search of the scientific literature to answer that very question (L. Cusack et al, Am J. Clin. Nutr. , 98: 99-104, 2013).

They identified 1415 scientific articles that had the phrase “blood type diet” in either the title or abstract. Then they begin the elimination process. They eliminated:

  • Studies done in test tubes, cell culture, or animals. Only human clinical studies were included.
  • Reviews, commentaries, letters or opinions. Those contained no original scientific research.

At this point they were down to just 16 published clinical studies. Then they asked which of those studies were designed to test the central hypothesis of the blood type diet. They asked:

  • Did the study start with human subjects grouped according to blood type?
  • Did the study have an intervention in which the subjects were required to adhere to a particular type of diet?
  • Did the study measure a health outcome of the dietary intervention?

Guess what? Only one study met these criteria. Just one! And it was a fairly weak study involving a totally different blood typing system than the ABO blood groups.

The Bottom Line:

1)     There is no scientific evidence supporting the blood group diet. A lot has been written about the diet, but nobody has actually shown that it works. The Emperor Has No Clothes!

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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Comments (5)

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    • Dr. Steve Chaney


      Dear Tiffany,
      Thanks for your comments. I definitely had help setting up the blog. I’m a scientist, not a tech expert.
      Dr. Chaney


  • Nancy Fickas


    You have done a fantastic job clarifying for us so much misleading information this is out in the news and on the web. Kept it coming I love to be able to have a source for accurate information. Nancy


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Recent Videos From Dr. Steve Chaney


Latest Article

What Causes Back Pain?

Posted April 21, 2015 by Dr. Steve Chaney

Natural Remedies for Back Pain


Author: Julie Donnelly, LMT –The Pain Relief Expert

Editor: Dr. Steve Chaney


What Causes Back Pain? 

Exploring the Overlooked Muscular Causes:


what causes back painYour back is a symphony of overlapping, interconnected, groups of muscles, tendons, and nerves. Each muscle merges into a tendon, which then crosses over a joint and inserts into a bone. When the muscle contracts it will pull on the tendon and the joint moves.

Your spine has 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae, each separated by a gelatinous disk that acts as a cushion to separate the bones and protect them from wear. Muscles span your entire spine, in some cases originating on the vertebrae and connecting each vertebra to the next, in some cases the muscles originate on the ribs and insert into the vertebrae in order to move your spine in the infinite number of angles, and in other cases the muscles originate on your vertebrae and insert into moveable bones such as your shoulder blade, pulling it in various directions.

In order to move in the opposite direction, the contracted muscle needs to relax to remove the strain from the bone, and the muscle on the opposite side contracts to pull the bone in the opposite direction. If the muscle that needs to release is in a spasm it can’t relax, and you have the muscles pulling in two opposite directions – and you have back pain.

The answer to what causes back pain is so broad that it needs to be broken down into four categories:

(1)   Why a Muscular Component Can Be What Causes Back Pain

Back pain is commonly caused by repetitively straining the muscles that insert into the vertebrae and ribs.  The list of muscles that insert into the bones of your back is long, with each muscle potentially causing pain when it is in spasm and pulling on the bone. Your back is a system of overlapping muscles, so many times when you are treating a muscle for one thing, you are also treating the source of a totally different problem.

This commonly happens when you are treating a thigh muscle that causes knee pain, but is also a key muscle that causes back pain, groin pain, and sciatica.

Natural Remedies for Back Pain

natural remedies for backTreating the muscle is one of the natural remedies for back pain. For this muscle treatment I suggest you use a 12″x 1 1/2″ length of PVC pipe and slide (don’t roll) from the top of your thigh to just above your knee.  The main area of treatment is shown in this picture.  It’s NOT on the front of your thigh, and it’s NOT on the outside of your thigh, but instead it is in between these two lines.

As you go down your thigh you’ll go over several “bumps,” which are actually large spasms that are pulling down on the front of your pelvis. The pelvis rotation causes a strain on your low back, and presses your posterior pelvis up into your sciatic nerve.

There’s a lot more to this muscle, but it’s so broad that it can’t be explained properly here. In fact, each of the muscles that cause back pain are fully explained, and treatments are demonstrated in my Trigger Point Yoga kit.

(2) Why a Bulging or Herniated Disk Causes Back Pain

herniated disk can be what causes back painThe disk between each vertebra is meant to be a cushion for the bones so they don’t rub on each other.  However, tight muscles that originate on each vertebra can pull the bones together, pressing down on the disks and cause them to either bulge in the opposite direction, or herniate.  For example, if the muscles on the right side of the spine are tight, they will bring the vertebrae closer together on the right, causing the disk to bulge toward the left.

If the muscles on both sides of the spine are tight, they will draw the vertebrae closer together and potentially cause the disk to herniate.

In either case the disks will put pressure on the spinal cord and causes back pain to be severe in that area.  However, if it is treated before permanent damage is done, releasing the muscle tension on the vertebrae will move the bones off the disk and the pain will be eliminated.

(3) Why a Vertebra Out of Alignment Can Be What Causes Back Pain

out of alignment can cause back painYour spine stays in perfect alignment because muscles are putting the exact amount of “pull” on each side. In fact, without muscles the spine would just hang straight and not be able to move at all — like a skeleton on a hook.  It is only because of muscles that the spine has any mobility at all.

The only way a vertebrae can move is either by a traumatic accident (such as falling down a flight of steps, or having a car accident), or by muscles pulling on the bones.

However, if muscles are pulling more on one side than the other the vertebrae will move toward the tight muscles.

The tension in the muscles must be released first if the bones are to be moved back into alignment and not be pulled out again by the tight muscles.

(4) Scoliosis, Osteoporosis, Spinal Stenosis, and other Causes of Back Pain

There are medical conditions such as scoliosis, osteoporosis, spinal stenosis, diabetes, and cancer that are also causes of back pain.  These are serious conditions that need medical attention.  It is always important to eliminate the possibility of any serious health risks before embarking on a path of treatment for back pain.


Obviously, as noted in #4 above, there are medical causes of back pain, but it is clear that the one that is consistently overlooked, and therefore not treated, is the muscular component.  My experience with thousands of clients over the years, both at my office and virtually online, is that muscles are frequently what causes back pain, and that the pain can be lessened or eliminated by treating the tight muscles demonstrating one of the natural remedies of back pain.

You have nothing to lose, and everything to gain, by exploring the muscular component to back pain!


Wishing you well,

Julie Donnelly


These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.


About The Author

julie donnellyJulie Donnelly is a Deep Muscle Massage Therapist with 20 years of experience specializing in the treatment of chronic joint pain and sports injuries. She has worked extensively with elite athletes and patients who have been unsuccessful at finding relief through the more conventional therapies.

She has been widely published, both on – and off – line, in magazines, newsletters, and newspapers around the country. She is also often chosen to speak at national conventions, medical schools, and health facilities nationwide.