"jamie" wrote in message
...
Hannah Gruen wrote:
Another, similar theory is that the tendency to develop insulin
resistance
was actually a helpful adaptation for early humans who may have been
faced
with feast/famine situations. Insulin resistance helped keep individuals
from storing too much fat during periods when food was very abundant.
Excessive obesity would have been a handicap for hunter/gatherers in
obtaining food, especially in lean periods when more effort would have
been
required. So as an adaptation to avoid super obesity, insulin resistance
would seem to have played a helpful role.

The problem for us in the modern world is that we never have lean
periods
following the periods of abundant food, and the insulin resistance gets
out
of control, overwhelming the pancreas' ability to produce insulin and
causing the chronic hyperglycemia we call diabetes.

Seems plausible to me I guess. The genetic tendency to develop insulin
resistance seems so widespread it seems kind of logical that there must
have
been something about it that helped survival.

I'm not following what you're saying. If insulin resistance promotes
more fat storage, how did it prevent excess fat storage?

It's the insulin itself that promotes fat storage. Insulin resistance
actually serves to slow the storage rate down somewhat, particularly when it
becomes severe. If you buy in to that theory, increasing IR is the reason we
didn't all just keep gaining and gaining and gaining until we weighed 500
pounds. Most of us tended to top off somewhere in the 200-300+ pound range.
Certainly there are a lot of exceptions to this, like the 600+ pound folks
who make news when they need to be taken to the hospital. But most people
don't get to that size.

Anyway, I'm not sure whether I buy into this theory of the origin of IR. But
there is a kind of logic to it that doesn't allow me to dismiss it.

HG