Richard Nikoley ( an interesting blog) posts his own thoughts on fasting and exercise, with his own experiences. It is a really good piece.
Isn't the conventional "wisdom" that fasting is bad because your blood sugar lowers too much; and by all means, "you don't want to exercise." After all, Zeus didn't make us like he made virtually all the other animals, who engage in their most strenuous activity of hunting when they're really, really hungry. Right?
He also points to Art Devany's comments:
Blood glucose will increase after a work out because the release of GH and stress hormones makes you insulin resistant for a brief time. That is why you don’t eat right after.The stress hormones also cause the release of glucose to supply fuel for the muscles, probably it is the glucagon causing the liver to dump glucose. This is not a problem if you don’t eat and is a reason I shoot baskets or take a nice easy walk after a workout. The cold bath will send all these hormones to go even higher.
Richard is also a bit of a fan of Eat Stop Eat