This is one question I have been asked many times. Everytime I talk to people about rare blood types, it seems someone in the crowd is interested in sharing the fact that she or he (usually she) has been on the blood type diet.
Of course I get asked what I think about it and normally I stay out of it, but I have to say that now I am looking at a study pretty much indicating what scientists have told me in the past in private.
Adherence to certain ‘Blood-Type’ diets is associated with favorable effects on some cardiometabolic risk factors, but these associations were independent of an individual’s ABO genotype, so the findings do not support the ‘Blood-Type’ diet hypothesis.
In other words: The diet has its benefits, but no correlation between blood types and what should be consumed has been detected when examining the formula given.