Just to reiterate the above. Your food is degisted and chemicaly cut up into its componant amino acids, sugars, carbs, vitamins etc before it gets into your blood stream. The digestion process is over before getting to the blood stream. Once in your blood your blood isn't going to have any way of knowing wether your arginine or whatever amino acid came from a roasted peanut or a roast turkey. So your food never really gets to find out exactly what type of blood you have and your blood never gets to find out exactly what food you ate.
To even remotely sound plausable the author would have to claim that certain blood types can utilise some amino acids better than others (rather than foods). Though I don't believe that there are any scientific studies backing this up either. Can the author cite experimental results published in respected, independant, referred scientific journals that back up his claims. Has the author done his own scientifically controlled/designed studies to test his theories. If not why not? If he has then have his studies been accepted for publication in an independent refered scientific journal. If not why not? If the author can't claim published results in refered journals then he can't really claim any acceptance of the theory by science at large. If this is the case (and I suspect that it is) then is it really likely that he is right and all other scientists in this field wrong on the matter of wether or not blood type is relevant to digstion? Personally I doubt that you have a solid basis on which to believe in his theories and in fact as stated above there is good reason to believe that it isn't a valid theory.
