Something to keep in mind is that insulin is not the only player here.
Protein also has a significant effect on glucagon and Gh.  In study after
study isocaloric diets with varrying amounts of PCF showed the most fat loss
or least fat gain on the lower carbohydrate diets.  Once again however this
is not the whole story from a Paloe/e-fitness perspective as one does not
endeavor to be skinny, but to carry appreciable amounts of (preferably) fast
twitch muscle.  As someone mentioned previously, insulin is highly anabolic
and one is hard pressed to gain muscle on a low carb diet.  Enter
macronutrient cycling in chich one carbs at specific times to enhance both
fat burning and muscle gain.  I suspect that Professor Devany will recomend
the macronutrient cycling in a highly randomized way.  Rob Faigan in Natural
Hormonal Enhancement recomends a highly structured plan as does John
Bernardi at testosterone.net(racy site, not for the faint of heart!).
Another thing to keep in mind is that latitude greatly influences the
availability, both amount and frequency, of fruit and carbohydrate
containing vegetables.  Interestingly as on goes farther north one on
average receives less light, and consumes more fat and protein.  This seems
to have effects on dopamine/serotonin levels.  None of this is simple
straight forward stuff.  Something which seems obvious is
overconsumption (perhaps frequency?) of carbohydrates increases the
likelyhood of syndromeX.  Treatment of syndrome X involves a reduction of
carbohydrates and hopefully increased physical activity.  Even though
protein carbs may create a similar hyperinsulinemic state, the two nutrients
are utilized very differently...moment to moment...day to day.