Dietary restriction (DR) by dilution of the food medium can extend lifespan in Drosophila. DR results in a state that is characterized by reduced fecundity, increased starvation resistance and higher total lipid levels. In the past, each of these correlated phenotypes has been proposed to play a causal role in the lifespan-extending effects of food reduction. However, more recent data show that each phenotype can be uncoupled from the long-lived state to varying extents. In this mini-review, we summarize the principal findings of the effects of DR on Drosophila in order to address what these phenotypes can tell us about the physiological remodeling required for Drosophila to be long-lived. Current data indicate lifespan-extension by DR is likely to involve both enhancement of various defense and detoxification mechanisms and a complex range of metabolic alterations that make energy available for these processes.