Nevertheless, accumulating data indicate that the temporal aspect of food intake, in addition to total caloric intake, can be important determinant of predisposition to chronic diseases ( Mattson et al., 2014), which now are the predominant cause of morbidity and mortality in developed nations ( Bauer et al., 2014). Furthermore, differences between metabolic properties of humans and those of small model organisms make it difficult to predict whether an 8–12 h eating window will impart physiological benefits in humans. A lack of methods and parameters to describe the daily eating pattern in humans makes it difficult to ascertain whether eating events in humans are spread over a long enough segment of the 24 h day such that there is an opportunity to reduce this duration. Such ‘time-restricted feeding’ (TRF) supports a robust circadian rhythm and is associated with reduced adiposity, elevated lean mass, longer sleep duration, increased endurance, reduced systemic inflammation, decelerated cardiac aging, gut homeostasis, and improvement in other clinically-relevant biomarkers.ĭespite these observed benefits in model organisms, the applicability of TRF for human health has remained unknown because the temporal aspect of human eating pattern is rarely measured. Conversely, recent studies in both nocturnal (mice) and diurnal ( Drosophila melanogaster) model organisms have demonstrated that restricting the time of caloric intake to a window of 8–12 hours without altering of the quantity or quality of diet can impart pleiotropic physiological benefits ( Chaix et al., 2014 Gill et al., 2015 Hatori et al., 2012 Sherman et al., 2012 Zarrinpar et al., 2014). Frequent caloric intake in animal models of diet induced obesity also dampens molecular circadian rhythms ( Kohsaka et al., 2007). Genetic disruption of circadian rhythms in experimental animals and behavioral disruption of circadian rhythm among shift workers likely perturbs such temporal regulation and predisposes to metabolic diseases ( Asher and Schibler, 2011). The circadian oscillator and time-of-feeding act together to drive daily rhythms in gene expression and protein function such that the anticipation of and responses to feeding events are properly timed ( Adamovich et al., 2014 Vollmers et al., 2009) every day. Therefore, molecular responses to feeding and fasting exhibit temporal dynamics with a 24 h period. Both food ingestion and fasting can alter the metabolic state. Consequently, organisms have evolved endogenous circadian oscillators that allow them to anticipate and prepare for activity, sleep, and food intake at a specific time of the day. Life on earth has evolved in the context of a 24-hour periodicity in environmental conditions and a dependent daily rhythm in food availability and predator avoidance.
0 Comments
Leave a Reply. |