Here is Becky's (our registered dietitian) feedback about this type of diet when another member asked about it:
"With genetic testing...someday we will be able to look at your blood at birth and KNOW exactly what diet to prescribe. HOWEVER, we are not there yet. There are several versions of blood type diets. AND while they may not be dangerous or harmful---there is currently NO TRUTH to the recommendations."
Hope that helps,
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford