>Right. So why are we going so far back to find health? I don't know the
>numbers, but I would venture to guess that the same holds true for cancer
>and stroke. We've had health a lot more recently than paleo times. I've
>read many books on paleo eating. I still don't know why we have to go
>back so far. Based on the above, we were ok before the turn of the
>century....
Certainly the changes in our diets over the last 200 years are the most
severe of all that occurred since the neolithic revolution, and their recent
appearance makes them all the more genetically unprecedented. Nevertheless,
the neolithic revolution was also severe and, relative to the time since the
appearance of our species, recent.
Anthropologists in the field have noticed the association of decreased
stature, musculature and dental health with agricultural sites to the point
that they can predict whether or not a skeletal find came from an
agricultural or foraging population by studying only the skeletal remains.
Apparently this is common knowledge among anthropologists, and I'm sure
you've heard this before, so excuse my repetition. That said, it seems that
your underlying question hinges upon how long it takes to fully adapt, and
whether or not "healthy" recent populations of primitive agriculturalists,
and all people before the indust. rev., have adapted.
Health studies of modern primitive agriculturalists are thought provoking,
but as Don said, questionable. Even so, I, too, would love to see skeletal
studies of, say, a single isolated culture, starting with its remains from
several millenia ago before agriculture, then a few hundred years after its
establishment, and finally thousands of years later ( primitive agr.
immediately before indust. revolution). I'd imagine it would be very
difficult to find a modern or recent group that you could positively
identify as descended from local fossil remains from the time surrounding
its first agricultural developement. However, let's assume that we have all
this info. on the N. Spanish dairy farmers, for example (do we?). In this
case, important issues for the sake of this discussion would be any increase
in health from earliest agriculture to recent pre-industrial, and in health
during foraging times. Who was better off, the prehistoric foragers or
their modern primitive-agr. (in this case dairy farmers) descendants? It's
a good question.
Given that we don't have any specific data, let's see what we can infer in a
wider sense. The foragers in this case would have been eating basically
the same types of food, albeit in slowly undulating ratios, for millions of
years. The contemporary (though primitive) agriculturalists, on the other
hand, have been eating their diet, containing only small amounts of those
foods available to the foragers, for perhaps 5,000 years (about 200
generations). Even if you assume that the foraging ancestors consumed
calf-stomach cheese when they found it (not an invalid assumtion), it is a
strictly seasonal food source that is also depends quantitatively on many
variables. Thus, it would have provided a yearly average of perhaps 1 or 2%
of the total caloric intake. The transition from this percentage, within the
span of 200 generations, to a life that depends so desperately on ruminant
milk (perhaps 40-60% total intake?) would have been a swifter and more
extreme dietary alteration than had been seen by the the entire duration of
ancestral existance, even during the most abrupt change in climate/
glaciation. The same can be said of cereal grains. I think that all
geneticists would agree to the fact that 100-300 generations are not enough
for any species to fully adapt to such a broad spectrum of changes as are
present among contemporary primitive agriculturalists, who eat both cereal
grains and dairy products as dietary staples.
So how far back is far enough? Certainly a diet consisting of only those
foods available to early agriculturalists and foragers before them is vastly
healthier than the average western diet of today. I would be interested in
hearing about studies of modern populations who eat this way and how they
compare to paleolithic populations. Regardless, I think that there is
strong evidence supporting the notion that the FUNDAMENTAL changes that
occured during the neolithic revolution are still very much an issue to
modern homo sapiens.
B. Lischer
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