Well, I don't know, but I do know that when people eat a lot of
carbs, a great deal of it is converted to fat anyway, *before it
is stored*.  If unneeded fat were eliminated from the body, it
seems that this fat would go too.


Paleo type eating is very low in carbohydrate - and technically any
carbohydrates would only be available for short periods in a "real"
paleo situation (i.e., coming across ripened fruit, ripened grain heads,
etc.)

And the reason you can lose weight on a Paleo diet is because it is low
in carboydrate.  Eating carbohydrates causes the release of insulin,
which is the hormone responsible for fat storage.  Without carbohydrate,
there is no insulin release and thus no fat storage.  In the absence of
the glycogen created by carbohydrate intake, dietary fat is burned for
fuel.  If not enough dietary fat is taken in to create enough fuel (and
it rarely is, except for those who eat blubber regularly), then body fat
is used.  

Protein is generally considered a poor source of fuel by the body, so is
generally not used for fuel unless consumed in extremely large amounts.
The body will prioritize fuel by the ease of its processing.  Sugars and
carbohydrates are the easiest to process, so it's the body's preferred
fuel.  After that, fats are more easily processed and broken down for
fuel.  

Protein uses up almost as much energy to break down and burn for fuel as
is actually contained in the protein, so the body will generally opt to
use dietary fat and body fat before attempting to break down protein
(either dietary or muscle) for fuel.  Protein is necessary for cell
growth and development, but is not a preferred fuel choice. 

So on a low or no carb diet (understand that means minimal insulin
release) - even if you are eating 50% of your diet in fat - on a 3000
calorie a day diet, that is 1500 fat calories (or about 168 grams of
fat) - your body is only getting 1500 usable calories.  If the remainder
of the diet is - say 1000 more calories of protein and maybe 500
calories of carbohydrate - then that means about only about 2000 usable
calories are being consumed by a body that requires 3000 calories - so
YES - body fat will start disappearing.  

This is, of course, an oversimplification, and I have pulled the numbers
out of the air for an example - but a simple way of understanding why
excess bodyfat will be burned on a paleo diet.

I'm not sure what Ray's reason was for the body's retention of fat was
(I must have missed that post), but I can tell you that the purpose of
bodyfat is manifold and important.  It's our own personal and portable
pantry.  High carbohydrate foods are naturally only available in the
warmer months and usually the ones before winter - and as a way to save
up for a thin winter when only meat is available, the body releases
insulin in the presence of these carbohydrate foods as a way to pad up
for the winter.  

Body fat is also necessary for regulating the female hormonal system.
Estrogen is produced and stored in bodyfat, and women without adequate
fat storage are unable to conceive and bear live young.  Extra fat
allows us to reproduce even in the leaner months - and reproduction can
continue through winter and will not be affected unless bodyfat levels
drop extremely low (under 12%) in times of long-standing famine (at
which point, reproduction is not the first priority, survival is). 

Hope this makes some kind of sense!

Fawn