Many thanks to each of you for your advice as well as the information, esp
that based on difficult personal experience.

I spoke with my son about this.  He's full-on into Paleo fitness and eats
low carb organic food using a mix of the <Warrior Diet> and <Natural
Hormonal Enhancement> guided by Neanderthin and a good understanding of
human evolution.  With the intellectual and moral certainty of youth he
pointed out that obesity is selected against in human evolution.  The
implication is that, all other things being equal, obese people could not
survive in the Pleistocene.  The same applies to people with other
physical or mental limits to an active, productive and cooperative
lifestyle.

So, he says, we don't know fro
m evolution whether serious obesity is
incurable.  No one - as far as we know - was ever born seriously obese, he
adds; they get this way.  Modern society makes it easy for the obese and
other people who could not survive in the Pleistocene to reproduce and it
may be that this expansion in human reproductive choices will lead to a
genetically [rather than environmentally] inherited obesity.

Any other thoughts?

Keith