For centuries, folklore and popular wisdom have linked poor eating habits and indigestion to nightmares and restless sleep. In A Christmas Carol , Ebenezer Scrooge at first dismisses the ghosts that torment him as mere dietary disturbances: “You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato,” he says to one spectral visitor. “There's more of gravy than of grave about you, whatever you are!" Earlier, Benjamin Franklin lamented that “[I]