The diet is meant to build a nutrition plan based around the ancestry of your blood type in order to replicate the foods you would have originally have been eating
group O is considered the ancestral blood group in humans so their optimal diet should resemble the high animal protein diets typical of the hunter-gatherer era
there is no scientific evidence to support the blood type diet hypothesis and no clinical evidence that it improves health, although they are a healthy diet choice one is not better than the other