Figure 1.

Gut hormones and adipokines with somnogenic effects. (Our example of pancakes with bacon and syrup is only one of many commonly ingested high fat, high sugar meals that could potentially induce the schematized gut and adipose somnogenic responses.) In response to ingestion of high fat, high sugar foods, the plasma carries increased glucose, insulin, leptin, cholecystokinin (CCK), peptide YY, and enterostatin, all of which have somnogenic influences when administered systemically. Increased mass of adipocytes over time will produce increased quantities of tumor necrosis factor-α (TNF-α), interleukin-6, and leptin. These substances have been shown to impair wakefulness, in part, by modulating orexin, serotonin (5-HT), and/or noradrenergic signaling. Which of these and other gut hormones and adipokines play significant roles in impairing alertness requires further study.