A couple of small notes on what Charles said...

Firstly, did't you say your "native paleo people" had only been in the area
for about 5k years?  That makes them relatively modern hunter-gathers, not
paleo... paleo-like perhaps, but paleolithic times were much before any
known record of humans in the Americas...  I don't mean to say they aren't
a reasonable guide--obviously, they did some adapting to what's local in
your area--very good.  However, they're at least as recent as agriculture,
so their adaptations aren't any more universal than those of agricultural
societies...  if I made *any* sense there :)

Secondly, not everyone does well on a fast...  appetite suppression,
increased energy, etc. are an annecdotal average--actual results may vary
widely and wildly.  fwiw.

Eating/not eating breakfast is also one of those things that vary from
individual to individual.  I, personally, eat only a little fruit in the
mornings--nothing else sounds good to me, nor sits well for the first 2-3
hours (or more) of my day.  For example, it's just after 1 pm and I'm just
eating my first meal of the day--I had a little fruit and a lot of water
this morning.  Some folks are the exact opposite, however--my dad's one.
If he doesn't eat a good solid breakfast, his hands shake by mid-morning.
Some folks even gain weight simply by eating later in the day.

Also, since different groups of humans (and their precursors) adapated to
different protein/fat/carb ratios, it's highly probable that where our
ancestor's are from have a lot to do with the ratios that are good for each
of us and should be taken into consideration (if there's a strong
particular geographic heritage, that is!)...

But that's what *I* think.

Personally, I don't ever think in terms of eating for energy or not.  My
energy levels are often more a product of how much water I've had--or at
least that's the more noticeable correlation, since I dehydrate quickly and
easily.  If I'm tired, I drink water.  If I've had water and am hungry,
then I eat, and eat what appeals at the moment.  I've found that by getting
rid of the refined stuff, sugars, grains, and dairy, I rarely want, much
less crave stuff, but I generally have a pretty strong desire for something
particular when I get hungry and if I take the time to figure out what,
that's generally what satisfies, and generally in a reasonable portion...
and if I'm paying attention to what I eat, I generally want to stop before
I eat too much--it's not longer appealing.  And that's even if the food's
cooked, btw :)

That's my, oh, $2.00 worth :)

Dianne