Dear Everyone,

In Arthur de Vany's last posting, he talked about the rationale for insulin
resistance being a mechanism that spares glucose for the brain in an environment
where dietary CHO is scarce.  To my knowledge, we were the first to put this
hypothesis forward in our paper 'The carnivore connection: dietary carbohydrate
in the evolution of NIDDM' in Diabetogia, 1994; 37: 1280-86.

We postulated that the ice ages (over the last 2 million years of human
evolution) resulted in a diet for many human groups dominated by game and marine
animals with very few plants and therefore high in protein and fat and low in
carbohydrate.  We believe this diet would select for more insulin resistant
genotypes.

We are in the process are obtaining more support for this hypothesis.  We have
shown that the plasma glucose profile after protein feeding is more favourable
(ie higher) in insulin-resistant people compared with insulin sensitive ones
(the latter show a decline in blood glucose). We've published this in abstract
form only (Proceedings of the Nutrition Society of Australia (1994,full details
on request) and are about to submit the full paper.

It is also interesting to note that acute exercise has exactly the same effect
on glucose metabolism at the cellular level as a pulse of insulin ie it
promotes glucose uptake into the muscle cells. Thus relative insulin resistance
would not compromise exercise performance (fight or flight!).  I can give you
the ref details on request.

Best wishes  Jennie

PS I thought Sarah Mason's points were very good ones.