I believe what Karl is referring to is the "enteric nervous system,"
which is neural tissue in the gut which functions separately from the
brain.  It coordinates gut functioning independently.  However, I think
Karl makes a leap of logic when he states that this is somehow related
to food cravings and nutritional needs.  The enteric nervous system
takes care of a lot of reflexes that keep the system going, like the all
too familiar "gastrocolic reflex, " which makes you excuse yourself to
go to the necessary room after a big meal.

Caroline, MD