LAUSR

Calorie restriction (CR) is a common approach to inducing negative energy balance. Recently, time-restricted feeding (TRF), which involves consuming food within specific time windows during a 24h day, has become popular owing to its relative ease of practice and potential to aid in achieving and maintaining a negative energy balance. TRF can be implemented intentionally with CR, or TRF might induce CR simply due to the time restriction. This review focuses on summarizing our current knowledge on how time-restricted feeding (TRF) and continuous caloric restriction (CR) affect gut peptides that influence satiety. Based on peer-reviewed studies, in response to CR there is an increase in the orexigenic hormone ghrelin and reduction in fasting leptin and insulin. There is likely a reduction in glucagon-like-peptide-1 (GLP-1), peptide-YY (PYY), and cholecystokinin (CCK), albeit the evidence for this is weak. Following TRF, unlike CR, fasting ghrelin decreased in some TRF studies, while showing no change in several others. Further, a reduction in fasting leptin, insulin, and GLP-1 has been observed. In conclusion, when other determinants of food intake are held equal, the peripheral satiety systems appeared to be somewhat similarly affected by CR and TRF with regard to leptin, insulin and GLP-1. But unlike CR, TRF did not appear to robustly increase ghrelin suggesting different influences on appetite with a potential decrease of hunger following TRF when compared to CR. However, there are several established and novel gut peptides that have not been measured within the context of CR and TRF, and studies that have evaluated effects of TRF are often short-term, with non-uniform study designs, and highly varying temporal eating patterns. More evidence and studies addressing these aspects are needed to draw definitive conclusions.