it is interesting isn't it. Takes nutrition to a whole new level actually. I have found, however, that certain proteins aren't the only thing to adversly or positively affect people, depending on their blood. Wheat, for example can cause weight gain in many people, along with rye, and lentils. But for others with different blood composition it can be just fine. It's important for people to know their blood type: A , B, AB, or O. That is a starting point to picking foods that will digest easily and those that will not.