Robert Kesterson
> ...at
> least in my case, my contention is that even being overweight 
> had more to  
> do with my activity level than my diet.  

That is certainly possible and I accept your explanation of your case.
However, for the sake of the more general discussion, I should point out
that there are some complicating variables that are difficult to separate
out. It is also possible that changes in metabolic rate were a factor. Since
you were not on a Paleo diet at the time we can't eliminate the possibility
that cumulative effects from eating a SAD affected your metabolic rate or
other biological processes. Still, given that your weight gain occurred
fairly early in life, it does sound like activity level was probably more of
a factor in your case (and a HG lifestyle of course involves higher rates of
activity than a standard American lifestyle).

> Throughout my young
> life (through  
> my early 20's), I was "skinny as a rail", and heard every 
> "bean pole"  
> reference possible.  Then in my early 20's I started slowly gaining  
> weight.  It took me 15 years to put on the extra weight.  My 
> diet during  
> those 15 years did NOT change -- my activity level did!  I 
> went from being  
> a kid who spent all his spare time hiking and fishing to an 
> adult who  
> spent all his time sitting in front of a computer,

In my case gaining weight had always been extremely difficult until I
reached around age 32, regardless of activity level and despite trying
weight lifting and eating plenty of high-calorie foods such as weight-gain
shakes to gain weight. I eventually accepted that I was going to stay thin.
Then starting around age 32 it gradually became much easier to put on weight
without trying to, again regardless of activity level. I was actually
exercising more because I was walking to work at the time. I think I
probably experienced a decline in metabolic rate. I went from having to make
a huge effort to put on a few pounds to having to consciously limit my food
intake to avoid quickly adding weight. Now that I'm eating Paleo I am again
finding it very difficult to add weight (despite eating more food than I did
during some of my heavier times) and having again to make a conscious effort
to add a few pounds. I'm actually exercising less than I was at my peak
weight range but weigh about 35-50 lbs less than I did during that period.
Either my metabolic rate has increased again due to my change in diet, or it
is just very difficult for me to gain weight eating Paleo foods.

> I am firmly convinced I could still be eating the SAD today,
> just paying  
> more attention to the quantities, and maintain my weight.
> 

Do you have to pay as close attention to the quantities on the Paleo diet?

> > A medium framed man of 6' 4" height is by American standards (which 
> > are heavier than the HG norm) supposed to range within 171-187 lbs. 
> > (which of course doesn't take into account percent muscle 
> mass--but my
> > understanding
> > is that HG's tend to be more muscled than Americans, not less).
> 
> The HG's must be *really* thin, then.  

Indeed, they appear to be. Also, you may have a "large" frame (more bone).
The "fattest" adult male HG's (Inuit) averaged your BMI of 24. The rest had
lower average BMI's--down to 19. In a HG people with an average adult male
BMI of 19, presumably half the men have BMI's below 19, though their ranges
are likely much narrower than in modern society, since all of the men are
eating the same types of foods and engaging in similar levels of activity.
Of course, BMI is not a perfect indication of leanness, but it gives a rough
idea, and if anything it likely underestimates how much fat modern people
would have to lose to match HG's for leanness. 

> At my lightest 
> bodyweight in recent  
> years, I was 185 lbs.  At that weight, I was lean enough to 
> clearly see  
> the lower abdominal muscles, and some of the veins on top of 
> them.  I  
> wasn't quite "cover model" lean, but pretty close.  For me to 
> get down to,  
> say, 175, I would have to lose muscle mass, something I don't 
> have that  
> much of to start with.  (It could be done -- in high school I 
> was about  
> 165 at this height, but I would not choose to be that thin 
> again.  I'd  
> have trouble showering if I turned sideways.  :-) )
> 

Since your activity level apparently did not increase during those 15 years
of weight gain, your weight gain in your 20's would presumably have been
mostly fat, rather than muscle. Speaking of visible abs, have you checked
out the 6-pack abs of the Bannock Indians (ca. 1880) in the photo in the
first issue of Dr. Cordain's newsletter
(http://thepaleodiet.com/newsletter/newsletters/PaleoNewsletterVol1Issue1.pd
f)? The Bannock were Plains Indians who hunted buffalo (American bison).
Note also how lean Dr. Cordain is. Or do a Google image search on Australian
aborigines to see how lean they can be when they maintain a traditional diet
and lifestyle and how obese they can get when they adopt the modern diet and
lifestyle. Ray Audette described himself as 6 feet tall and weighing 145
lbs., which would give him a BMI of 19.66, towards the lower end of the HG
BMI range. You can check out his photo here:
http://sofdesign.com/neanderthin/observer.html. It appears that the leanest
HG's tend to be those that eat more (wild) land-based meat (like bison or
kangaroo) and less starches or sea animals and don't live in the cold
Arctic, where the Eskimos have apparently been naturally selected for more
fat cells. Most Americans would call the traditional Bannock Indians,
Cordain, Audette, and traditional Australian aborigines "skinny."

> > Since HG's tend to be fairly well muscled, BMI if anything likely
> > underestimates the level of obesity of moderns compared to HG's.
> 
> Exactly.  Which is one of the reasons I dislike BMI as a measure of  
> anything.
> 

My point is that any errors in estimating leanness and body fat in the case
of BMI would likely favor moderns, since they tend to be less muscled than
HG's. So more accurate measures would likely reveal that moderns would have
to lose even MORE weight to match the leanness of the HG's. In recent years,
some health authorities have been putting out the opposite message--that
being a little plump is actually healthy. Some scientists have pointed out
that their data indicating that plump people are healthier than lean people
is likely skewed by those who lose weight due to illness. If the HG data are
any indication, to achieve optimum weight and health modern people would
likely have to lose more weight (and reduce their LDL more) than most health
authorities and scientists realize. Since I don't know of any HG's who
consciously limit or count their calories, and the HG San of the Kalahari
eat about the same amount of calories per day as Americans (2,140 /day
according to Richard B. Lee,
http://minnesotamusings.wordpress.com/2006/12/03/the-kung-san) and have
access to an essentially limitless supply of mongongo nuts when in season,
yet don't get fat, HG leanness seems to have less to do with calorie
counting than with the types of foods ingested. Physical activity also plays
a role, of course, but it's interesting that San women are lean like the men
despite walking about half as far per day (Cordain, The Paleo Diet).

> I'm nothing special at all, *everyone* should be this healthy.
> 

That's right, and it would be possible if we hadn't long ago exceeded the
earth's capacity for sustaining people on a HG diet and lifestyle.