There are only a few proposed aging interventions that have met such stringent criteria: fasting regimens, caloric restriction, exercise, and the use of low molecular weight compounds, including spermidine, metformin, resveratrol and rapamycin (Table 1). From a molecular point of view, these interventions may act through epigenetic mechanisms (histone acetylation/methylation), the insulin/TOR pathway, the Ras signaling pathway, mitochondrial function, proteostasis, autophagy, and stress resistance.