If you haven’t read Petro Dobromylskyj’s posts about Physiological Insulin Resistance, then just go do it. Highly recommended.
I’ve written about it as well, albeit in a slightly different context:
What is our proper “natural” diet?
40 years ago a group of researchers turned ketosis into poetry.
But now on to more pressing matters. In the food deprived state, Physiological Insulin Resistance develops, in part, to spare muscle (yea yea yeah and glucose for the brain). But how much of this is due to ‘food deprivation’ per se as opposed to something else… like circadian rhythms.
Exhibit A. Hat tip to Dr Kruse for writing about this TED talk. In it, Jessa describes a crab that lives on the beach; scurries up the beach when the tide comes in and back down when it goes out. Scientists captured a few, flew them halfway around the world and put them in little tilted cages. The crabs still scurried up & down, in time with the tides.
Exhibit B. Evidence that the lunar cycle affects human sleep. People tend to sleep a little less during the full moon. Subjects were recruited to a windowless sleep lab and had no exposure to sun/moon/anything outside – they maintained this circadian rhythm for 3 days (Cajochen et al., 2013). Different from the crabs, but similar (in a way).