There is strong evidence to indicate that disrupted sleep (reduced sleep duration and/or quality) leads to reduced glucose tolerance, reduced insulin sensitivity, and dysregulation of appetite.103 Consequently, disrupted sleep has been reported to be associated with the increase in risk of developing T2D.104,105 It has been hypothesized that altered gut–brain satiety and insulinotropic signaling may contribute, in part, to these observed metabolic defects. This evidence concerns the gene INS and type 2 diabetes mellitus.