On Fri, 28 Aug 1998, Michael Audette wrote:

> Just look to any 3rd world country today, where the child mortality rate is
> high, birth rates are high, and the population is high. You can't say, its
> because of better food, or medical conditions.

I agree, but I don't know who was saying that.

James Crocker pointed out that CR delays fertility.  Delayed
fertility would tend to slow population expansion.  We know that
population expansion *accelerated* with agriculture.  This
doesn't prove that pre-agricultural diet was CR, but it does lend
some plausibility to the idea.

There's a lot we don't know, and may never know, about
pre-agricultural peoples.  Their caloric intake is one such item.
In all probability, it varied tremendously, from season to season
and place to place.  We don't know much about their longevity
either.

I think James Crocker's point is that CR is readily *compatible*
with paleolithic diet, and it is quite possible that CR was a
reality for many pre-agricultural hunter-gatherers.  His point
that longevity is not something that would have a high priority,
in terms of natural selction, is well taken.  Human health and
survival are most important, in evolutionary terms, during the
time of having and raising children.  It is success in these
activities that ultimately constitues "fitness."  This doesn't
mean that there is no evolutionary payoff to longevity beyond the
child-bearing/raising years, since elders can bring advantages to
the gene pool in other ways (e.g., grandparents are available as
parents when the actual parents are killed).  But these
advantages would be secondary.  Selection pressure in favor of
healthy longevity would always be secondary to selection pressure
in favor of healthy youth.

Interestingly, the fewer calories a person consumes, the less of
a drain that person is on the resources of the group.  It's
almost as if evolution can only "afford" to tolerate longevity
under conditions of low impact on resources.

Of course, I'm just speculating.  Another way to think of it
could be this:  Suppose we are born with a sort of lifetime
caloric account, from which we draw every time we "spend" a
calorie by eating and burning it.  When we have spent all the
calories, we die.  Aging is our account "statement."  The CR
philosophy, then, is budget caloric spending to get maximum
duration from the account.  Bizarre as this sounds, it would be a
way to balance longevity with conservation of resources.

Todd Moody
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