Circadian rhythms govern homeostasis and organism physiology. Nutritional cues act as time-givers, contributing to the synchronization between central and peripheral clocks. Neuronal food-synchronized clocks are thought to reside in hypothalamic nuclei such as the ventromedial hypothalamus (VMH) and the dorsomedial hypothalamus (DMH), or extra hypothalamic brain areas such as nucleus accumbens (NA). Interestingly, the metabolic sensor NAD(+)-dependent deacetylase SIRT1 is highly expressed in the VMH and was shown to contribute to both control of energy-balance and clock function. We used mice with targeted ablation of Sirt1 in the Sf1 neurons of the VMH to gain insight on the role played by this deacetylase in the modulation of the central clock by nutritional inputs. By studying circadian behavior and circadian gene expression we reveal that SIRT1 operates as a metabolic sensor connecting food intake to circadian behavior. Indeed, under food restriction and absence of light, SIRT1 in the VMH contributes to activity behavior and circadian gene expression in the SCN. Thus, under specific physiological conditions, SIRT1 contributes to the modulation of the circadian clock by nutrients.