Over the last decade, cellular glucose metabolism has emerged as a central player in the mechanisms of programmed cell death (PCD). We examined the metabolic foundations of apoptosis from a Darwinian context and suggest that PCD has evolved from the cellular response to metabolic stress, most notably in relation to glucose metabolism. Whilst apoptosis and other forms of PCD are essential to the development, maintenance and survival of multicellular organisms, it is now evident that controlled and selective cell death confers fitness advantages in unicellular organisms. All species may thus harbour a fundamental relationship between the availability of basic nutrients and life/death decisions. This evolutionary perspective may inform our understanding of PCD in its many guises.