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


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Recent Videos From Dr. Steve Chaney


Latest Article

Stretching Exercises For Flexibility And Pain Relief

Posted June 21, 2016 by Dr. Steve Chaney

The Pluses And Minuses Of Stretching

Author: Julie Donnelly, LMT –The Pain Relief Expert

Editor: Dr. Steve Chaney


muscle knotsWhen using stretching exercises for flexibility and pain relief, you should be careful to release the knots first.

Minuses!  Are there any minuses to stretching?  Yes, there are…let me explain.

All muscles originate on one bone, we’ll call the bone that is at the beginning of the muscle the “stationary bone,” then the muscle tendons cross over a joint and insert into another bone we’ll call the “moveable bone.”

When the muscle contracts (shortens) it pulls on the tendons, and they pull on the moveable bone where they are inserting.  This is how all joints move.

Let me demonstrate with the biceps muscle in your upper arm.  Your biceps originate in two different places:

The “long head” is deep inside your shoulder joint, and the “short head” is on a bone at the top of your shoulder called the coracoid process of your shoulder blade.

muscle painYour biceps tendon crosses over the inside of your elbow joint and inserts into the bone in your forearm.

When your biceps contract, you bend your elbow so you can touch your shoulder.

Notice that your triceps, on the back of your arm, are having to totally stretch to allow this movement.

Imagine what will happen if your triceps won’t stretch.

You won’t be able to bend your arm and your elbow will hurt.  You may decide that you need to stretch your triceps – but this is where the “minus” comes in!

The “Minus” of Stretching Exercises for Flexibility When Your Muscle is Tight

stretching exercisesWhen you repetitively use a muscle, in this case the triceps, the muscle fibers spasm and become painful, tying them into knots that are shortening the muscle fibers.  The fibers are now short, but they are still originating and inserting in the same place.  This causes a strain on the bone, usually at the insertion point.

If you had a 12″ length of rope and tied enough knots in it to make it 11″ and then consider what would happen to the rope if you tried to stretch it back to 12″ without first untying the knots.  The knots would get tighter and the fibers outside of the knots would be overstretched. This is what happens to your muscles when you stretch without first releasing the spasms.  It is the main reason you may feel worse after stretching than you did before you stretched.

Also, since the fibers are now short, they can’t lengthen enough to allow the joint to bend.  In this example, the triceps have shortened which prevents them from lengthening. You either think you need to strengthen your biceps, or you think you need to stretch your triceps.

Rarely does anyone think about first releasing the spasms, and then stretching the muscle fibers.  Yet,  this is exactly what needs to be done if you plan on using stretching exercises for flexibility and pain relief.

Release the Spasms  Preventing You From Using Stretching  Exercises Safely.

release spasmsAs I mentioned, when you try to stretch you are now causing the knots in the muscles to become more complicated, and you are overstretching the fibers on either side of the knot.

However, if you release the spasm by putting direct pressure on it, you will feel a burning sensation, but as you press and release, the burn will lessen until it totally disappears.  Now you can safely stretch for flexibility without injuring any of the muscle fibers.

The Perfect Stretching For Flexibility Packages:

Two products that will demonstrate how you can safely release the spasms and then start stretching for flexibility

The 15 Minute Back Pain Solution


Specifically written to focus on each muscle that causes back pain. THE 15 MINUTE BACK PAIN SOLUTION explains in detail why the muscles from the middle of your back to your knees will cause low back and hip pain, including sciatica and what to do to relieve the pain.  An easy-to-read eBook that has a step-by-step program you can do in 7 Days.

This is the perfect way to prepare your muscles so you can use stretching exercises for flexibility!


Focused Flexibility Training

back pain solutionThe comprehensive stretching program covers all aspects of releasing the spasms that have shortened the muscle fibers, and then guides you through a safe stretching routine using proven yoga-style postures.

Focused Flexibility Training has three DVDs that:

  1. Demonstrates how to do every Julstro self-applied treatment taught in Treat Yourself to Pain-Free Living.
  2. Two 30-minute yoga-style stretching programs for the upper body
  3. Two 30-minute yoga-style stretching programs for the lower body.

Both stretching programs featured in the DVDs start with a 15-minute routine of Julstro self-applied treatments to release spasms in the muscles being stretched and then continue on to the 30-minute guided stretching programs.

Focused Flexibility Training also comes with a Julstro Perfect Ball and a Bamboo Stick Massager to provide all the tools you’ll need to be safely stretching for flexibility.

With just a bit of time and focused attention on safely stretching, you will be able to get back to living your life without joint pain and with more flexibility than ever before – it’s easy and it feels great!

Wishing you well,

Julie Donnelly


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.

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.