How are foods determined to be in the beneficial category?
The food does not agglutinate that blood type.
The food does not raise the Urinary Indican (bowel toxicity) in that blood type.
The food protects against some disease with a known preference for that blood type, and does not show any negative aspects.
The immunological design of the digestive tract seems to indicate a distinct ability to metabolize the food well, perhaps as a result of anthropology or other variations.
The food contains an enzyme known to react positively with the antigen of that blood type.
The food does not stimulate an opposing blood group antibody reaction.