PT on the Net Research

Blood Type Diets


I have been doing quite a bit of reading on metabolic typing and have a question concerning the issue of blood types. If somebody is positive or negative (i.e., B positive, A negative), does this have any effect on the foods they shouldn’t eat as shown in Walcott and Fahey's book “The Metabolic Typing Diet?” I can’t seem to find much on this question!


This is a great question and one I get asked quite often. Despite popular belief, the blood type diets recently popularized are actually not correct. They have not provided the “clinical results” that are being claimed. In fact, with metabolic typing, we see just as many individuals with “carnivore” blood type A as we do “vegetarian” blood type O. When I say clinically, I mean in terms of what diet produces the desirable results, whether this means general health and fitness, weight loss, back pain elimination, strength benefits or recovery from any disease such as diabetes or cancer or any other problems your clients have.

It is important to remember that the issues people complain about are their symptoms, and by eating correctly based on their genetic requirements (using metabolic typing), one can achieve optimal health and wellbeing, which then eliminates whatever the individual was suffering from as a result of not eating correctly for his metabolic type in the first place. Based on the research I have done on blood typing, I am convinced that the only useful information that “blood type” provides is regarding the few blood type specific lectin foods in those who have significant digestive disorders. Thus, to answer your question, the “positive” or “negative” has no clinical value in metabolic typing.

Another thing to keep in mind when analyzing any diet or nutrition system is to look at how much research has been done prior to publishing the book or program. One of the most impressive aspects of metabolic typing that no other diet program out there can claim is that it is a comprehensive compilation of over 70 years of clinical research by many different individuals, including medical researchers, physicians, biochemists, dentists, physiologists, nutritionists and psychologists – many are giants in their fields and world renowned in their respective scientific and clinical disciplines. Therefore, you can rest assured knowing that the metabolic typing program your clients or patients are following is the best choice to achieve optimal health and vitality.