Jens Wilkinson wrote:

> but one problem with
> this is that to create natural selection, a problem
> has to kill people before they reach childbearing age.

Actually, if people who are genetically constituted in such a way that they
can stay reasonably healthy on a diet of Budweiser and McDonalds were to
have more children than average then those genetic traits would spread
throughout the population over many generations. This could happen if such
people have more sex than average, or if they are less likely to use birth
control than the average, or both. 

This is probably a real phenomenon happening right now in the human
population. I would not be surprised to learn that use of birth control is
inversely associated with consumption of beer and junk food. I seem to
recall there is already strong evidence that use of birth control is
associated with socioeconomic status; that people of low income and low
education tend to have more children than wealthy educated people, at least
in the USA. If this is true then it is not a great leap to say also that
people of low income and education are more likely to drink beer and eat
junk food. 

However as people who subscribe to paleodiet theory we have to say also that
this problem is hardly relevant. We cannot say that we're on the verge of
breeding a nation of drunk Big Mac eaters without also contradicting our
belief that humans are not adapted to dairy and agriculture even after
12,000 years. It is a central tenet of our theory that human metabolism
evolves slowly. 

I certainly hope Ronald McDonald is long dead and buried 12,000 years from
now. By then we should be colonizing other planets and controlling our own
evolution with genetic engineering. If the human species is still going to
be eating Big Macs and french fries in the year 14,000 then someone please
just shoot me now. :)

-gts