Dick Bird's questioned the evidence regarding differences between modern
man's genome and that of paleolithic man.  Clearly, the suggestion that
there are minimal differences can only be inferred.   The amount of
mitochondrial DNA diversity in various human racial groups from around
the world has been determined (1), additionally the rate of
mitochondrial DNA change can also be estimated (1,2).   Based upon this
rate of mDNA change, as well as similar nuclear DNA studies (3), the
genetic differences between humans living 40,000 yrs ago and those
living today  ago can be estimated.   A similar approach has been used
to determine if Neanderthals were precursors to modern humans or were
separate species (4).
        I agree that small genotypic differences can result in large
phenotypic differences.   Also, there are a number of genotypic
differences among various human populations that are known to have been
elicited by diet (i.e. adult lactase persistence and a variety of
hemoglobinopathies, and perhaps the degree of insulin
resistance/sensitivity) since the agricultural revolution.
Consequently, modern human genomes (particularly in those populations
with the greatest exposure to agriculture) are not identical to our
paleolithic ancestors, and some of these slight genetic differences may
have important health ramifications for modern man.   However, basic
human nutritional needs seem not to have varied significantly since
paleolithic times.   All humans require similar ranges of both macro and
micronutrients and all human groups have similar anatomical,
physiological and endocrine functions in regard to diet and nutrition.
The reason for these similarities is because of our common evolutionary
experience - we were all hunter gatherers dependent upon wild plants and
animals - and these dietary selective pressures shaped our present day
nutritional requirements.

                                Cordially,

                                Loren Cordain, Ph.D.