I don't know how male and female diets varied among H-Gs; it would have
depended on the region.  I do know, however, that the metabolic needs of
modern individuals can differ significantly.  Although this is a gross
generalization, some people thrive best on a light diet and some on a
heavy one.  In the U.S., far more women than men fall into the latter
category.  For this reason, I suspect the absurdly strong emphasis on
light diets will fade as medical researchers pay more attention to
women.

Cheers,
-- Aaron Wieland