Relax. If you buy this book and read it carefully, it is a guide for losing weight, not for general health. Dr. D'Adamo and his father stumbled upon this research quite by accident, treating overweight people in California. I personally am Type A+ (which forbids peppers and tomatoes -- "nightshade" type vegetables). But I say to hell with it. On the other hand Type A is the true vegetarian type, and Type O the carnivorous type. I am a vegetarian, and in that respect, Dr. D'Adamo's research is right on target, for me. This is a much too complicated matter for a couple of posts to an Internet list. Really. Rob