On Sun, 14 Nov 1999, Hans Kylberg wrote:

> Just because we have ancestors who lived in the tundra this does not
> mean that that became an optimal environment.

This is a good point.  In particular, we tend to assume that
paleolithic people were robustly healthy throughout all these
changes in climate and location.  But, as my biologist colleagues
are fond of pointing out when we discuss this stuff, we don't
know that at all.  We know that they *survived* these changes,
but that doesn't mean that there weren't health trade-offs.  They
like to point out to me that there are always trade-offs, and the
fact that a species manages to survive on a certain diet doesn't
imply that the diet is ideal for that species, in terms of the
health and longevity of individual members.  It only means that
the diet is "good enough" to keep the species going. And of
course the obvious proof of this is the Neolithic revolution
itself.  In evolutionary terms, agriculture is more "successful"
than any paleolithic way of life ever was, simply because it
supports large numbers of people.

It seems that the Inuit achieved a workable trade-off in the form
of a ketogenic diet, allowing them to survive and reproduce in
good health, but tending to shorten their lives somewhat.  In
evolutionary terms this is a good deal, even if as individuals we
might want to find a better arrangement.

Todd Moody
[log in to unmask]