SatietyAssociatedwithCalorieRestrictionand Time-RestrictedFeeding:PeripheralHormones

Abstract

Calorie restriction (CR) is a common approach to inducing negative energy balance. Recently, time-restricted feeding (TRF), which involves consumingfoodwithinspecifictimewindowsduringa24-hday,hasbecomepopularowingtoitsrelativeeaseofpracticeandpotentialtoaidin achieving and maintaining a negative energy balance. TRF can be implemented intentionally with CR, or TRF might induce CR simply because of thetimerestriction.ThisreviewfocusesonsummarizingourcurrentknowledgeonhowTRFandcontinuousCRaffectgutpeptidesthatinfluence satiety.Basedonpeer-reviewedstudies,inresponsetoCRthereisanincreaseintheorexigenichormoneghrelinandareductioninfastingleptinand insulin.Thereislikelyareductioninglucagon-likepeptide-1(GLP-1),peptideYY(PYY),andcholecystokinin(CCK),albeittheevidenceforthisisweak. After TRF, unlike CR, fasting ghrelin decreased in some TRF studies, whereas it showed no change in several others. Further, a reduction in fasting leptin,insulin,andGLP-1hasbeenobserved.Inconclusion,whenotherdeterminantsoffoodintakeareheldequal,theperipheralsatietysystems appear 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 increaseghrelin,suggestingdifferentinfluencesonappetitewithapotentialdecreaseofhungerafterTRFwhencomparedwithCR.However,there areseveralestablishedandnovelgutpeptidesthathavenotbeenmeasuredwithinthecontextofCRandTRF,andstudiesthathaveevaluatedeffects of TRF are often short-term, with nonuniform study designs and highly varying temporal eating patterns. More evidence and studies addressing theseaspectsareneededtodrawdefinitiveconclusions.