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.