I just learned that The Blood Type Diet existed. Skeptic that I am, I immediately thought it was a scam, but I thought that I’d do well to look into it a little and find out what the theory and causational links are supposed to be. Web MD has an article about the diet that is quite balanced and not completely critical. Then I looked at the web site of Peter D’Adamo, who dreamed up the diet, and all I found were irrelevant comments that didn’t tell how this is supposed to work. That got me to wondering ...