A diet for life

In a number of organisms, dietary restriction has been shown to extend lifespan at the expense of reduced fecundity. An example of competition for limited resources, the thinking generally goes, as nutrients are reallocated from reproduction to somatic maintenance. Grandison et al. now demonstrate that, in Drosophila, dietary restriction does not induce reallocation, because different amino acids limit lifespan and fecundity. They find that fecundity in long-life flies can be rescued by the addition of methionine alone. Long lifespan and high fecundity can thus occur simultaneously, without dietary restriction itself, by adjustment of the ratio of amino acids in the diet. These findings imply that humans might be able to enjoy the benefits of reduced food intake, without the downsides, by adjustment of dietary nutrients.