Not necessarily news, but it does put some numbers to it.

http://jcem.endojournals.org/cgi/co.../jc.2006-0382v1

Makes me think that had I lifted hard all through college, I wouldn't have fattened up nearly as much as I did.

Oh, and the link only goes to the abstract, so if someone can find the entire paper, please post it.

it is formatted with line numbers on each page of the PDF and all the figures and charts are at the end - but if you click on the line in the upper right hand side box that says "author's manuscript" you can read it.

Why do people persist in getting it backwards. Insulin resistance causes obeisty, not the other way around. There's some evidence that visceral adipose tissue is hormonally active in ways that contribute to IR, but it's insulin that promotes visceral adipose tissue in the first place.

LisaS, thank you for pointing that out. And making me feel kind of silly for asking.

ceberezin, I'll let you take that up with the peer-reviewed researchers.

sorry - guess I could have pm'd you

I think exercise rather than having a long effect on insulin sensitivity only has an acute effect. GLUT4 receptors transfter from the cytoplasm onto the cell membrane which enhances the uptake of glucose. But soon as you stop exercising this process is reversed within 2-3 days. So for sensitivity diet and weight plays a much more important role in staying insulin sensitive.

or regular exercise
the normal phenotype of a fit human is driven by both diet and exercise - the fact that GLUT4 might be downregulated when the person is sedentary is an example of the body conservinig resources - not an argument against exercise. The physiologic "norm" is probably to have GLUT4 around and to have regular vigorous exercise. Continual sedentary behaviour is the aberration, not regular exercise.

anyone with interest in this subject might like the work by Frank Booth.
Here are some links to get you started:
Exercise and gene expression: physiological regulation of the human genome through physical activity. J. Physiol. 2002 543:399-411 http://tinyurl.com/hrgbq
Waging war on modern chronic diseases: primary prevention through exercise biology J. Appl. Physiol. 88:774-787 2000 http://tinyurl.com/ko7qk
Eating, exercise and “thrify” genotypes: connecting the dots toward an evolutionary understading of modern chronic diseases. J. Appl. Physiol. 96:3-10 2004
http://tinyurl.com/fs2d7