I'm sure that given enough time, if the blood type diets are followed correctly they can work for many. However; if they do work, it is partly because the author advocates the elimination of highly processed and refined foods in favor of a more natural organic food diet. More importantly though, is the lack of scientific evidence from the author, who claims that these diets work for the stated reasons.My own personal investigation of these claims, shows that some information is completely missing and some of it has been twisted to fit the authors paradigm. As an A blood type, the high carbohydrate diet, as advocated by ER4YT, had some undesirable results for me, such as weight gain, and an unacceptable rise in blood cholesterol and triglycerides.I would suggest, that if you are looking for scientific evidence of the relevance of the blood type diets, to read Human Blood Cells: Consequences of Genetic Polymorphisms and Variations, Imperial College Press, by editor May-Jean King. Steve Henry and Bo Samuelsson both PhD scientists, and experts in this area, have devoted an entire chapter on the ABO polymorphism that explains the irrelevance of the blood type diets.