The Answer Is in Your Bloodtype: Research Linking Your Blood Type and How It Affects Your Life Span, Love and Compatibility, Your Likely Illness Profile, Diet & Exercise for Maximum

"Book was very valuable to me as I learned that Type B blood types should avoid CHICKEN as it contains a protein that causes the blood to clot. This led to a cure for severe sinus drainage and a cure for my asthma."
~ Written on 2008-03-16

"I haven't finished reading it yet, but it just seems that Personal Nutrition USA, Inc, who self-published this book, did so only to specifically sell their brand of protein shake, Personal Protein.

Whether or not there's actual substance to what they're trying to prove in this book, that alone should send up some red flags..."
~ Written on 2007-11-26

"In large bold print, the book quotes Albert Einstein as saying, "THE THEORY IS CORRECT ANYWAY." This simple quote serves as the foundation for Joseph Christiano and Steven Weissberg's theories in The Answer is in Your Bloodtype. This book was written to educate people about what their blood type can potentially translate into. The authors claim that knowing one's blood type is important for staying healthy, eating well, and having good relationships. The Answer is in Your Bloodtype, although "written by a renowned physician and an internationally known fitness expert," makes superfluous scientific claims without any strong evidence. The assertions that the authors make may seem to make sense, but when further analyzed, are nothing but pure pseudoscience.

The book begins with a thorough explanation of human blood groups. The analysis of the anthropological distribution of the four blood groups (A, B, AB, and O), their trends in diet and exercise, and various "interesting phenomen[a]" related to each blood group are presented in the first few chapters. For example, the authors note that "almost every" older smoker "tends to be Type O," a phenomenon that they give no scientific evidence to besides "what [their] research shows." The book continues by giving evidence of blood group on longevity, disease, and sexual compatibility. The book rounds off by providing "grocery lists" for each blood type and a seven-day menu for both active and inactive persons of each group.

It seems likely that the authors intended The Answer is in Your Bloodtype for people interested in improving their fitness and well-being. The book does indeed touch on various subjects that would pertain to this audience: nutrition, exercise, spiritual and social well-being, etc. It also gives suggestions for people in each group regarding what foods they should purchase and what foods they should avoid. The authors do a good job explaining the rudimentary aspects of nutrition science but the more complex areas are lacking evidence.

Although The Answer is in Your Bloodtype is presented as a scientific breakthrough, the book is full of individual case studies without a compilation of statistical data and analysis. The first appendix, for example, contains a list of research subjects. Whereas actual scientific case studies would be presented as statistics, the authors list their research as "Jose L., smokes heavily, tortured in Nicaraguan prison, age (67)." The authors seem to believe that a mundane list of worthless information will suffice for scientific evidence. Additionally, when data is presented it is usually followed by an extreme conclusion without any proof. For example, "In our research, we found individuals who were A2 by virtue of their muscle mass, but had to eat vegetarian to stay healthy. Those who did not follow a vegetarian diet invariably developed high blood pressure or heart disease." Logical flaws such as this are not uncommon in this book.

As a final note, the authors illustrate the validity of their research (as pertaining to personality) by listing a "small portion of the JFK, Jr. family tree." President Kennedy is used as, yet another, case study due to his blood type - "John Fitzgerald Kennedy is the only confirmed blood type AB president in the history of the United States." The authors go into great detail about President Kennedy's unique life, his personality, marriage, and the various people he met (as if one's blood type would predict who one will meet.) The information is mere fluff, an excuse at trying to give backing to their research. Yet, "in terms of The Theory of Compatibility, it is [all] explainable."

The Answer is in Your Bloodtype does a wonderful job at keeping a biochemist, such as myself, entertained. The heavy emphasis on believing the authors without any scientific proof renders this book at most as a work of fiction. Research linking one's blood type to health and personality does indeed exist. Publications regarding the scientific validity of the theory can be found from 1927. Dr. Weissberg and Joseph Christiano, however, do their utmost best to keep this information a secret. They end the book with yet another quote of Einstein: "God does not play dice with the universe" -- The Answer is in Your Bloodtype."
~ Written on 2007-03-11

"Many people claim they lost weight on the blood type diet, but look more closely, regardless of your type. Eat lean meats, fresh fruits and vegetables, Essene bread instead of commecially prepared white or wheat, and stay away from sweets and processed foods. Common sense. I have relatives who were blood type A that died in their 80's and a few in their 90's, and some of them were smokers. Sorry, but I don't buy into the "fact" that type A's are guaranteed to die before 70 years of age unless they take extra special care of themselves. However, I do agree that A types are more prone to stress and anxiety than type O's and that A types have low stomach acid, since I'm type A and never took antacids a day in my life and I know numerous O's who munch on them like candy."
~ Written on 2004-06-25

"I read this book and it caused me more anxiety than it helped me. I am a type A and very negative things are said about the A bloodtype. Like one other reviewer said, this is like a doomsday book. No way will I ever read this type of book again! I think that the author should have been a little more sensitive."
~ Written on 2004-01-19