• dietary restriction;
  • appetite;
  • aging;
  • reproduction;
  • evolution;
  • antagonistic pleiotropy

Abstract: A diverse array of organisms live longer under dietary restriction. Here, a hypothesis is proposed as a framework for interpreting this phenomenon. Dietary restriction is explained in terms of evolution and antagonistic pleiotropy. Focusing on the decline in reproductive capacity seen in dietary restriction, it is submitted that “normal” appetite is geared toward producing a neuroendocrine and metabolic internal milieu optimized for reproduction, with long-term detrimental effects on health as a by-product. In dietary restriction experiments, the animal is prevented from eating enough to attain this internal milieu and, as a by-product, lives longer.