I am a newcomer to the list and am working my way through the archives.
I first read the Paleolithic Prescription the year it was published
(@1988?) and have always had it in the back of my mind as I  have
encountered the well known cycles of media hyped diet advice and a
lifetime of acquired taste bad habits.  More recently,  I have read
everything I can find on the efficacy of a vegetarian diet and was not
able to find anything coming close to scientific validation for it from
the evolutionary perspective.  I could not get past the necessity of B12
and the fact that hominids must have,  at an early stage, evolved the
dependance from animal sources. All other large primates ingest animal
protein  ranging from primarily insects (gorilla) to the small but
significant meat intake of chimps.  However,  the meat is relatively
infrequent.  I find on these pages that many of the readers  feel that
meat should be eaten at every meal;  by my observation,  much of the
support for this comes from the Sears camp.  Please do not take me for
a  proselytizer;  I am only searching for information that will help me
decide these interesting issues for myself.  I do wonder if anyone can
point me to the best scientific sources for support of the proposition
that  homo sapiens sapiens should be eating meat everyday.  I was
impressed by the T. Colin Campbell  China study that found a strong
correlation between  a plant based diet and low frequency of
degenerative disease (cancer and cardiac:  I cannot recall the stats on
diabetes).   Is anyone aware of serious critiques of this study?  I also
note in the archives that there seems to relatively small emphasis on
the roughage aspects of the evolutionaly diet.  It seems reasonable to
assume that bowel transit time and the micronutients available from a
wide variety of plant foods are key factors distinguishing  the paleo
diet from the typical American diet.  I should also say that the authors
who indict transfats pose an intriguing theory;  I am wondering if
anyone is aware of population studies that take this into account.  For
example,  I have often seen references to the Seventh Day Adventist
population in plant based diet articles.  Has that group been the
subject of any truly scientific studies?  Obviously,  I have many
questions and few answers;  I look forward to learning from these very
interesting pages.