NAFLD originates from fat buildup in the liver owing to unbalance in biological processes, all of which are hallmarked by 24-h rhythmic fluctuations driven by the biological clock: lipid metabolism, metabolites/bile acids fluxes, signaling pathways downstream of nutrients, ligand bound nuclear receptors, gastro-intestinal hormones, as well as host gut barrier-microbiota interface, autophagic and immune/inflammatory processes. The gene discussed is CLOCK; the disease is metabolic dysfunction-associated steatotic liver disease.