Aging is inevitable for almost all the organisms. Aging processes vary from one organism to another. It has been shown that many organisms have lifespan-regulation mechanisms in common. Dietary restriction is the most robust non-genetic interventions to ameliorate aging and aging-associated diseases in many organisms. Reducing overall calorie intake was thought to be a crucial factor for dietary restriction -induced longevity. However, recent studies indicate that both the meal timing and lowered intake of specific nutrients rather than overall calorie intake are important for lifespan regulation. These findings shed light on new aspects of mechanisms underlying dietary restriction -induced longevity. The genetic factors are also shown to be involved in dietary restriction-induced longevity. This review summarizes the dietary interventions and the genetic factors that mediate lifespan extension by dietary interventions.