Aaron Sugarman wrote:

>I am not sure, but our ancestors ate very lean meats, which I think was
>MacDougall's point. [...]

I'm not an authority on this subject either, but I think that you are only
half right.  It is true that wild game tends to be much leaner than domestic
livestock, but this doesn't imply that our ancestors ate a low-fat diet.
First of all, it is necessary to understand that hunter-gatherers who lived
in a cold or arid environment ate a low-carb diet.  It is possible to eat a
diet which is low in fat or low in carbs, but not both.  Our ancestors
prized the fattier portions of the animal, and favoured organ meats over
muscle meat.  A few animals, such as ducks and geese, are naturally fatty.
Bear grease, etc. could be mixed with dry meat.  If a lot of lean meat was
available, but not much fat, then most of the meat was probably "wasted."

-- Aaron Wieland