Yes, as Jens points out, most of the evidence for the decline in health at
the dawn of agriculture comes from bone remains. Cordain and others cite the
archeological research. Among other things stature decreased dramatically
during the Neolithic, something like 4 or 5 inches. However, since that time
stature has been increasing, such that moderns are almost if not as tall as
paleos. If stature is any indicator of general health, (and I'm sure it is),
then this is evidence that our health is really not that much worse than
paleos. The same analysis can be made with life expectancy. Life expectancy
dropped radically at the advent of agriculture, but since then it has been
rising steadily.

On balance, 21st century people living in first world countries might even
be healthier than paleos even before they adopt a paleodiet (though I won't
make that argument). My point is simply that we shouldn't deceive ourselves
into thinking paleos were dramatically more healthy than moderns. Paleos did
not have access to our advanced health-related technologies. All we really
know for certain is that agriculture and animal husbandry tend to have a
negative effect on health.

-gts