Months ago I talked about Doug McGuff, MD, and John Little's book entitled "Body by Science."
It's one of the most informative books on the relationship of muscles, strength and metabolism I've run across.
I recently ran across a video of a lecture by McGuff that's worth watching because he does an excellent job describing the dynamic relationship between muscles, glucose, and metabolic syndrome, the plague of civilization and underlying cause of the obesity epidemic.
Body By Science from Pinpoint Multimedia on Vimeo.
While I don't subscribe to his narrow view of exercise (he dismisses aerobic exercises like running and biking in favor of high intensity torture on weight machines), he has a deep understanding of the role of muscle in health, especially people who are trying to lose weight.
We tend to think of diet and exercise as separate topics, but after watching McGuff you'll see why it's critical to have muscle and exercise all three types of your muscle fibers hard, not just the slow twitch ones.