The role of fat in C. elegans aging. Recent studies imply that lipases and lipid desaturases can mediate signaling effects on aging. However, the exact molecular processes underlying this phenomenon still remain unclear. On pages 466–471 of this issue, Daniel Ackerman and David Gems give more insights into possible mechanisms. Aging worms show a widespread increase in deposition of fat and increased levels of yolk lipoproteins. This ectopic fat deposition may cause lipotoxic effects, contributing to the age-related decline in tissue function. On the other hand, removal of the germline in C. elegans extends lifespan by inducing/increasing lipase, autophagy and FAT-6 desaturase expression, thus leading to a healthier lipid status.