The worsening global epidemic of obesity has increased the urgency of research aimed at understanding the mechanisms of appetite regulation. An important aspect of the complex pathways involved in modulating energy intake is the interaction between hormonal signals of energy status released from the gut in response to a meal, and appetite centres in the brain and brainstem. In particular, the gut peptides cholecystokinin, peptide YY, glucagon-like peptide 1, oxyntomodulin and pancreatic polypeptide have been implicated in signaling satiety post-prandially. The ultimate goal of work in this field is the development of effective treatments for obesity, and manipulation of these gut-brain axes offers potentially useful strategies for the conquest of this significant cause of morbidity and mortality and future burden on healthcare systems worldwide.