The assumption that dietary restriction (and drugs that mimic its effects) will extend both lifespan and healthspan jointly has come under question, based on research involving 160 genetically distinct strains of fruit fly. Noting that results may foreshadow what will happen in humans eating a Spartan diet, researchers report that thirteen percent of the strains were more vigorous, yet died sooner with dietary restriction; 5 percent lived longer, but spent more time in poor health.
