Many studies have described the positive effect of food restriction on aging and longevity in rodents as well as a genetic pathway activated in response to starvation in nematodes and mice. This genetic pathway may be conserved across phyla and some authors are convinced that these studies could help delay aging, particularly human aging. I suggest that these studies are analyzing a rescue program used to resist starvation but not active in ad libitum-fed animals. Whether these studies provide an increased understanding and ability to delay aging under the usual living conditions of animals and humans is unclear. The study of hormesis is proposed as a way of studying aging under normal living conditions, because ad libitum-fed animals subjected to mild stresses can live slightly longer than control animals and display increased resistance to strong stresses. It would be of interest to study, in animals subjected to a mild stress inducing hormesis, the response to non-lethal stresses rather than lethal ones, because elderly people are more often confronted by such non-lethal stresses (e.g., temperature drop in winter) than by lethal ones.