Satiety Associated with Calorie Restriction and Time-Restricted Feeding: Central Neuroendocrine Integration

Abstract

This review focuses on summarizing current knowledge on how time-restricted feeding (TRF) and continuous caloric restriction (CR) affect central neuro-endocrine systems involved in regulating satiety. Several interconnected regions of the hypothalamus, brainstem, and cortical areas of the brain are involved in the regulation of satiety. Following CR and TRF, the increase in hunger and reduction of satiety signals of the melanocortin system (NPY, POMC, and AgRP) appear similar between CR and TRF protocols, as do the dopaminergic responses in the mesocorticolimbic circuit. However, ghrelin and leptin signaling via the melanocortin system appears to improve energy balance signals and reduce hyperphagia following TRF, which has not been reported in CR. In addition to satiety systems, CR and TRF also influence circadian rhythms. CR influences the SCN (suprachiasmatic nucleus) or the primary circadian clock as seen by increased clock gene expression. In contrast, TRF appears to affect both the SCN and the peripheral clocks, as seen by phasic changes in the non-SCN (potentially the elusive food entrainable oscillator) and metabolic clocks. The peripheral clocks are influenced by the primary circadian clock but are also entrained by food timing, sleep timing, and other lifestyle parameters, which can supersede the metabolic processes that are regulated by the primary circadian clock. Taken together, TRF influences hunger/satiety, energy balances systems, and circadian rhythms, suggesting a role for adherence to CR in the long run if implemented using the TRF approach. However, these suggestions are based on only a few studies, and future investigations that use standardized protocols for the evaluation of the effect of these diet patterns (time, duration, meal composition, sufficiently powered) are necessary to verify these preliminary observations.

Effect of lunch with different calorie and nutrient balances on dinner-induced postprandial glucose variability

“…Starvation with time-restricted feeding (TRF) is now a popular way to reduce obesity, risk of cardiovascular disease, abnormalities in lipid metabolism, and diabetes [ 35 , 36 ]. Men with prediabetes were randomized to TRF (6 h feeding period, with dinner before 3 p.m.) or a control schedule (12 h feeding period) for 5 weeks and were later crossed over to the other schedule.…”

Time-restricted eating improves health because of energy deficit and circadian rhythm: A systematic review and meta-analysis

“…Some studies explored whether TRE could enhance metabolic health, 23 , 24 and others attempted to understand whether these benefits could exist in the absence of energy restriction or were modulated by the eating time of day. 25 , 26 …”

Fasting diets: what are the impacts on eating behaviors, sleep, mood, and well-being?

“…The suprachiasmatic nucleus (SCN), or primary circadian clock, is mostly affected by the CR diet, and both primary and peripheral circadian clocks are influenced by TRF. The peripheral circadian clocks are the parts controlled by eating timing, sleeping, and other lifestyle factors ( 128 ). Food deprivation can cause changes in peripheral clocks mediated by switching from nocturnal to diurnal eating ( 129 ).…”

“…Thus, it seems that the hunger-satiety balance following a CR diet probably inclines toward hunger, which is less probable to occur after TRF diets. Dissimilar to the CR diet, improved calorie balance and mitigated hyperphagia following TRF have been mediated by ghrelin and leptin alterations through the hypothalamic melanocortin system ( 128 ). However, currently there is a gap regarding the alterations of several gut peptides related to satiety regulation by fasting diets.…”