A simplified scheme for metabolic proteins that are involved in longevity. There are complex interactions among individual metabolic signaling pathways, such as the insulin/IGF1, TOR, AMPK, sirtuin and FOXO pathways. These interactions impact healthspan and longevity. For instance, the TOR pathway, which is activated in situations of nutrient excess, is not only linked to other nutrient-responsive pathways, such as the insulin/IGF1 pathway, but also to the CR-induced pathway involving AMPK and Foxa activation. Longevity promoting proteins are in green, proteins that when mutated increase longevity are in red, other proteins are indicated in blue; mammalian protein names are used.