Blood types have been linked to nutrition almost since they were
discovered.  Several factors limit the validity of the generalizations
made from the linkage of specific blood types to ethnic groups and diets.

In order for us to eat "forbidden fruit" we must evolve an order (ie
the order Primata) in order of magnitude.  Ten thousand years is not in
this order of magnitude!

Mathmatically, the most distantly you can be related to any other human
is 11th cousin.  Many pure-bred dogs have a longer pedigree than that!
In evolutionary time this is an eyeblink!

Although some ethnic groups do have increased tolerances to things like
lactose and glucose related to their long histories of
pastoral and agricultural subsistance, the "diseases of civilization" are
still the most common forms of death in all people who consume technology
dependent foods (see May '97 Lancet).

Our ancestors may not all been hunter-gatherers - but they were all
Primates!

Ray Audette
Author "NeanderThin:A Caveman's Guide to Nutrition"
http://www.sofdesign.com/neander