Figure 1.

Synchronization between central and peripheral clock genes. In the above illustration, we observe that the breakfast in synchrony with downlight “turns on” the clock, activating the CLOCK:BMAL1 complex. It drives the transcription of PERs, CRYs, REV-ERBs, RORs genes, PPARγ coactivator 1α (PGC-1α), SIRT1, and other transcriptional elements promoting downstream expression of several proteins encoded by tissue specific “clock-controlled genes,” relaying the clock information to cellular processes. As a result, β-cells insulin response and muscular GLUT-4 activity are optimal in the early hours of day. Hence the glucose response after isocaloric meals is significantly higher in the evening than in the morning.