In regards to earlier discussion of fats and their possible significance to
the early diet, the following paper by Dr. Laura Corr (reprinted from the
European Heart Journal) may be of general interest:

 http://www.syndicomm.com/corr.html

Note that this paper does not address ancestral diet issues directly.
However, it is frequently suggested in some circles that modern humans in
Western nations suffer from an epidemic of heart disease because of high
intake of fats in general and saturates in particular, because (it is
proposed) the human metabolism did not evolve to handle large amounts of
fat in the diet.

Other sources on this list, such as Loren Cordain, have suggested that late
paleolithic humans may in fact have depended heavily on the animal fats of
megafauna for their energy needs.  If fat is not the dietary bogeyman it
has so frequently been painted as in the last two decades, this hypothesis
may be easier to swallow.  If eating generous amounts of fat does not make
people sick, and lowering fat intake does nothing to make people healthier,
then there's some indirect support for this idea.

The article at http://www.syndicomm.com/lowfat.html (authored by yours
truly) may also be of some interest, although it's been mentioned on this
list before and so many have probably already read it.