Very interesting, and I think pretty intuitive. Gary Taubes talks about this when he preaches that Cals In and Cals Out are not independent variables. From my own personal experience, and I'm sure anyone that has dieted can corroborate this, when cals in are low, so is general energy level.
Darryl et al, any data on how resting calorie usage changes depending on the number of surplus calories available? I've observed that during hypocaloric periods, my resting body temp, sleep cycle, and other thigns drastically differ. I would also venture a guess that I have more "nervous energy" usage when relatively well-fed (tapping my foot, drumming my fingers, etc.).
"Use what talents you possess: the woods would be very silent if no birds sang there except those that sang best." —Henry Van Dyke