Waaay back Dean wrote:

> One of the most common arguments advanced by advocates of
> vegetarianism and by some other commentators on health is that humans
> evolved as vegetarian or mostly-vegetarians.  The most frequently
> forwarded argument to advance this position is that human tooth and
> jaw structrure are clearly those of herbivores with flat molars,
> excellent sideways chewing motion and with a clear lack of sharp
> teeth for killing prey.

Homo has lousy sideways grinding compared to real hervivores:
bovines, horses etc.  Our jaw doesn't work very well that way by
comparison.

We lack the long gut of horses and/or multiple stomachs of ruminants
that are essential to their ability to process raw grain and more
appropriately grass and/or browse.

We don't process green leaves of most plant species.  Cabbage, kale,
lettuce etc. sure.  Grape leaves somewhat if very young/early.  Not
much else other than fruit.  Try eating whole grain w/o milling and
extensive cooking: you'll break your teeth.  Try eating a minimally
significant amount of grass: it won't stay down.

We don't process grain (seeds of grasses) well unless cooked.

We handle nuts and some seeds fine.

We've evolved using other tools for handling meat: hands and cultural
adaptations: stone tools.  We got into stone tools long before the
rise of Homo; stone tools appropriate for processing animals for
meat, hides and other tool material, not for processing grain until
very recently (5000-8000ya, then as microblades for scythes and
concurrent with rise of agriculture demonstrated by other artifacts).

I think _Paleolithic_Prescription_ details our evolution very well.

You want a real herbivorous hominoid: look at the robust
Australopithecines: A. boisei; A. robustus.  Their molars were easily
twice the dimensions of ours; their incisors and canines easily less
than half the size of ours.  They had large sagittal crests:
attachment for huge chewing muscles.  Their teeth are found to be
heavily worn as by dirt etc. in their food implying grain and seed
eating.  Depending on one's cladistics they are high probability a
divergent branch of our ancestral A. afarensis (Lucy), not as likely
our direct ancestors.  They're extinct.

Other herbivores: Gorilla gorilla.  Much more evident canines than
ours.  Similar molars.

Omnivores: Pan paniscus & Pan troglodytes: the chimps.  Dentition
much like the gorillas.

I think we must conclude that dentition isn't much of a guarantee of
dietary interpretations.

I saw a moose mandible yesterday.  The molars looked more like a
dog's than man's.  !

> I most recently heard a snippet of this line of thinking on a
> popular news show here in America called "Nightline" in which a
> medical doctor and health writer advanced this view.
>
> I wonder if anyone among our membership would like to comment on
> this line of reasoning?

Perhaps such 'reasoning' is more likely rationalizing.

Ah... noting that chimps are regular hunters and meat eaters and
their primary meat source is other primates perhaps one can imagine
as Joseph Campbell (_The_Way_of_the_Animal_Powers_) did that the
extinction of the robust vegetarian Australopithecines is at least
partly due to the dietary practices of various carnivores including
early Homo.

Physical anthropology shows that the last of the ancestors of the
primates were insectivores this probably being responsible for our
dependence on concentrated vitamin, protein and fat sources.