Thanks for the good points and questions, Carrie, Cynthia and Todd. They
really put my views to the test and helped me flesh out my understanding of
these topics.

Philip:
> If exercise is a major factor that can overcome dietary factors, how 
> do we explain the Northwestern Pacific Indians who were reportedly 
> fairly
sedentary 
> > fishermen but apparently were not obese?

Carrie:
> *** It is hard to generalize about PacNW Indians since there were so
> many different groups and lifeways changed over time, but you may be
> underestimating the "exercise" involved in fishing for huge 
> salmon and marine mammals. 

Yes, that's why I said "fairly", though it would have been more clear if I
had said "relative to nomadic hunter-gatherer groups." The PacNW Indians
would certainly be less sedentary than moderners, but the permanently
settled ones would also seem to be more sedentary than nomadic or
semi-nomadic groups. I haven't heard anything to indicate they were in
significantly worse shape than the nomads, and the PacNW indians I have seen
images of have mainly looked lean, though Chief Seattle looked a little
pudgy and stooped in his older years. If there were any tribes that were
consistently obese, I'm not aware of them.

Carrie:
> The archeological record shows specimens in
> excellent health except for a relatively high frequency of dental 
> abscesses caused by excessive tooth wear from the hot rock cooking
method.

I haven't heard of this, how did cooking with hot rocks cause tooth wear? Is
there a reference I can look at to learn more about the archeological data
and health of the PacNW Indians? I haven't seen as much regarding them as I
have other HG populations and they would seem to be an important group to
consider, given their relatively rare combination of HG diet with permanent
settlement among some of the groups.

Philip:
> > Lions do not get fat amidst plentiful antelope, yet domestic 
> > housecats
do become obese
> and often remain obese despite owner's efforts to limit their calories 
> and let them exercise.

Carrie:
> *** The effort needed to bring down an antelope is significantly 
> greater than that needed to chase a string for a few
minutes.

Cynthia Kuni:
>  ... the antelope may be plentiful, but the lion still has to go out 
> and
chase it, 
> risk the horns, hooves, etc.

OK, if you don't like that example then you could use a comparison of more
similar animals like a bobcat or other small wild cat that doesn't have to
bring down large game and still doesn't get fat, despite not consciously
counting or limiting its calories. Or you could compare wild lions to zoo
lions, or obese zoo lions to lean zoo lions. Obesity is a problem for lions
at some zoos, but not for wild lions. I don't think that lack of exercise
accounts for the entire problem and I'll bet that a wild lion could get
quite obese and even eat itself to death on pet food, even while running
around in the wild, if such food were made available to them. 

I believe this basic problem occurred in Yellowstone National Park, where
grizzlies who are not caged and are free to roam the park nonetheless became
quite fat from eating trash, food left out at campsites, and food that
people fed them. I saw an extreme case where people were feeding horribly
obese grizzlies on TV and a ranger said something like, "These bears have
already become dependent on this food, so we allow it to continue so that
they won't starve." The people were feeding them complete junk like Twinkies
and the like. I wondered at the time why they couldn't at least require the
people to feed them something less horrendous.  It was very sad to see. The
exercise activity of grizzlies likely diminished somewhat when they learned
to scavenge campsites instead of hunting the woods (especially the grizzlies
in that one area who were being fed every day), but not to the point of a
caged animal. I think there are also zoo animals that are kept in relatively
restricted pens and still don't get obese because they are fed a relatively
species-appropriate diet. 

Or maybe this example would be better: a lone wolf comes across an abandoned
elk carcass. Will the wolf eat itself to death by trying to consume the
whole carcass in one go? An identical twin of the wolf comes across a giant
open bag of kibble. Will it eat itself to death by trying to consume all the
kibble in one go? Both wolves exercise equally. My guess is that the first
wolf will not eat itself to death, whereas there is a good chance that the
second wolf will (or at least make himself quite sick), regardless of how
much the second wolf had been exercising. I think this may be because
species-appropriate foods signal satiety better than inappropriate foods,
and I believe Todd said something to this effect. This says to me that,
while exercise and calories are certainly important factors, the type of
food is more important--and that seems to be the case for many species of
animals. There are exceptions to this generalization--such as endurance
athletes who can eat tons of carbs and still stay lean (though they may pay
for it in other ways)--and maybe the hummingbird, because that little sucker
gets a LOT of exercise. :-)

Cordain has provided some additional explanation and evidence for why
aerobic exercise alone doesn't promote substantial weight loss (at least in
the short run) and why diet alone may be "just as effective as diet plus
exercise in causing weight loss" (though I think I have seen studies that
found that weight lifting helped with losing significant body fat in a
relatively short span of time)...

	"Imagine that a mildly obese woman weighing 154 pounds, would like
to lose 30 pounds, or 105,000 calories, by walking or jogging for 3 miles
(forty-five minutes) a day. . The 3-mile walk/jog causes a net deficit of
135 calories--not a lot, considering the amount of work she's doing. At this
rate, it will take her 26 days to lose 1 pound and 780 days (more than 2
years) to lose 30 pounds. Most [people trying to lose weight] simply don't
have the patience to wait that long." (The Paleo Diet, p. 200)

One of the studies Cordain cited to back this up is here:
http://listserv.icors.org/SCRIPTS/WA-ICORS.EXE?A2=ind9911&L=PALEOFOOD&P=R190
38&I=-3&X=263F9B37521A0AED11&Y=the411%40fastmail.fm

Of course, aerobic exercise provides other benefits, even if it doesn't help
with short-term weight loss. As Ray Audette said, "The reason to exercise
aerobically is not for weight loss but to improve your cardiovascular
stamina." In other words, to build up your heart muscles. Also, in the
longer run, Cordain points out that aerobic exercise improves insulin
metabolism/sensitivity, which reduces fat deposition and may reduce
appetite.

C. Kuni:
> *** Of course type of food matters. Cats and dogs fed 
> species-appropriately do not become obese and diabetic like so many 
> kibble-fed ones do, even if
> they do not get as much exercise and might be desireable.

Yup, thanks, that was my point. It's good to get confirmation from someone
who knows much more about cats and dogs than I do.

C. Kuni:
> If humans had to work hard
> physically to get their food, perhaps we would not be so inclined to 
> overeat.

Yes, the availability and convenience of modern foods is certainly a factor
that contributes to increasing obesity.

C Kuni:
> I feed my cats whole mice and day old chicks (from
> http://www..rodentpro.com), a species-appropriate diet, but one of 
> them still wants to eat more than his share and we restrict his 
> ability to eat freely.  Something about it laying on a plate... a 
> luxury the lion never knows.

That's interesting. Do you think your cat would become obese if it were
allowed to eat as much mice and chicks as it wanted, and why do you think
one cat wants more while the other(s) don't? 

> How shocked my friends were at a recent news article that recommended 
> 90
minutes of 
> exercise per day. My old buddies at Weight Watchers would bathe in 
> glory
if they got in 20.

Interesting. I also think dietary change can make exercise more enjoyable by
increasing energy levels and reducing pain. I know a retired athletic
director in his 70's who regularly exercised more than probably 99% of the
people his age, but he had to take plenty of ibuprofin every day to keep his
osteoarthritis pain down so he could do it. When he switched to a
gluten-free and then Paleo diet his arthritis pain went away and now he
enjoys exercising more than he ever did and doesn't need to take ibuprofin
any more. He says he's playing tennis and raquetball better than he has in
probably 20 years and beating some regular players who are in their 30's and
40's.

Todd:
> In the case of Sears, I think it's a matter of deciding that 
> paleolithic nutrition provided some confirmation for conclusions that 
> he had reached in other ways. ...

I have noticed that as a general tendency. People tend to look for tidbits
that confirm their existing views, even if the broader context that they are
taken from contradicts their views. It would make sense for Sears or
Simopoulos to cite some of the minor points of Paleolithic nutrition to
support their case, but if they pretend that the basic principle supports
their diets, I think that is a stretch.

In Simopoulos' case it was particularly strange because she devoted a
chapter to explaining the broader Paleo theory and then basically ignored
its implications. It seemed like she was saying, "The Paleo theory of
nutrition makes sense, now here's a traditional Greek diet that includes
plenty of non-Paleo whole grains, to which I've added some non-Greek goodies
like bagels so you'll like the meal plans." I know that she thinks we only
have to eat MORE like our Paleo ancestors, not just like them, but it was
surprising how much her meal plans and recipes varied from the foods of our
Paleo ancestors.