Blood type diet type diet hypothesis and no clinical evidence that it improves health. Peter J. D'Adamo, a naturopath, is the most prominent proponent of blood type diets. Luiz C. de Mattos and Haroldo W. Moreira point out that assertions made by proponents of blood type diets that the O blood type was the first human blood type requires that the O gene have evolved before the A and B genes in the ABO locus; phylogenetic networks of human and non-human ABO alleles show that the A gene was the first to evolve. They argue that it would be extraordinary, from the perspective
ABO blood group system in test tubes, and not only that some human blood also agglutinated with animal blood. He wrote a two-sentence footnote: This was the first evidence that blood variation exists in humans – it was believed that all humans have similar blood. The next year, in 1901, he made a definitive observation that blood serum of an individual would agglutinate with only those of certain individuals. Based on this he classified human bloods into three groups, namely group A, group B, and group C. He defined that group A blood agglutinates with group B, but never with its own type. Similarly,