Becky Root wrote:
>..Isn't it the case that homo
> sapiens sapiens existed in the Americas during the paleolithic era, and
> that
> they too were hunter gatherers?

Yes, probably since some 10k years.
As far as they ate it, it has the advantage that the consumtion is
proven to be save. At least for Native Americans, indians.
The same would apply to wheat and lentils, as they were eaten as the
main staple of humans of Eurasian ancestry. That would be the most
people in today's America (English, French, German, Irish, Spanish,
Greek, Portugese, Arab, Israel etc.).

However if you think that there is a genetic *adaption* necessary to be
able to cope with some food items or the chemical components in them
you'd have to look back to times when genetic adaptions could occur.
(As far as genetic adaption would be necessary!)
How long does a genetic adaption need to take place?
500 years (Europeans in America)? 7000 years (neolithicum)?
120,000 years (appearance of the first anatomically modern humans)?
2,000,000 years (appearance of the first hominids)?

I am sceptic of the genetic point of view.
The human genome is to 98% identical with the ordinary mouse.(!)
The nearest, with 98.5% is the chimp.
Maybe it's the other way round.
Changes occured in the *shape* of hominids.
These were better (or lesser) capable to rely on certain food resources.
For example a hominid capable of walking around in the hot savannah day
was able to gather more nuts and tubers, catch more animal prey.
Some other food now was better suited to nourish the differently shaped
human body. A little denser. And no more harsh leaves (Gorilla food) as
we have less of a cellulose fermenting colon.

I also think it's possible that the real adaption  to food items occurs
within the traditions of human group.
Some indians developed the ability to nourish on acorns (oak nuts) by
the necessary soaking and leeching and by knowing the beneficial edible
amounts and combinations.
Inuit developed the ability to rely on 95% meat by eating it raw,
avoiding toxic livers and combine with enough proper fat.
Bandkeramik people (Europe, 5000BC) developed the ability to rely on
wheat and lentils by combining with little of flax, goat and sheep milk
and meat and a little game. And primarily by proper processing
techniques like soaking, fermenting, heating.

New food items contain new toxins and new traditions to know how to eat
them without long term problems.
Industrial techniques (since at most 100 years) pose a lot of new
toxicity and combination problems never encountered before.
Like mass agriculture, lost traditions, conservation toxins, pesticides
and now- due to genetic "engineering" new lectins and antigens in many
traditional food items.

regards

Amadeus