>Since the Australian Aborigines have only been there for about 40,000
years,
>all the usual arguments about "evolving" with a diet would answer this
last
>question - they haven't had time to adapt.

Huh? Adapt to what? First, we have no clue what their 'average' carb intake
was over the past 40,000 years - they may have adapted from a higher to a
lower carb intake as far as we know. And, as Todd pointed out, it depends
on what you consider to be 'high carb' (high sugar). If it has been medium
to low all this time, then of course no adaptation needed to take place.

>Paleo man from northern climes would have access to fruit about 6 weeks of
>the year. this leaves 46 weeks to be in ketosis

I live in a 'northern clime'. Obviously, it is not as frigid now as it was
during the last ice age, but I would guess our climate would approximate
more southern regions of that era. And we have far more than 6 weeks of
fruits (or carbs in general, for that matter). More like 16-20 weeks of
various fruits, berries, tubers, etc. Many of those could easily be stored,
especially frozen when the cold season hits. Which would reduce your
ketosis estimates to 32-36 weeks. (Even in the high mountain regions around
here the fruit and berry season is more than 6 weeks).