We study the biology of aging using the fruit fly Drosophila melanogaster as a model. It has been known for some time that reduced dietary intake extends lifespan in many diverse organisms including invertebrates, mammals and even single-celled fungi. Recent studies aimed at understanding this phenomena have uncovered conserved genetic pathways utilized by diverse species, that appear to regulate aging. These cellular and organismal genetic pathways regulate metabolic processes in response environmental factors such as nutrient compoition and availability. It is quite likely that metabolic state and its regulation by genes in these pathways can significantly affect life-span.