Since the 1930s, scientists have known that animals fed restricted diets when young—including water fleas, rats, fruit flies, and mice—tend to live longer. But the biological mechanism bridging a meal eaten in infancy to health outcomes weeks or months later has remained unclear. A new study, led by Fumiaki Obata, a biologist at the RIKEN Center for Biosystems Dynamics Research in Kobe, Japan, may have found the answer.
Obata's team discovered a protein that carries a record into adulthood of what fruit flies ate as larvae, influencing their longevity. The researchers manipulated the diet of lab fruit flies during the larval stage, reducing their main protein source (yeast) from 8 percent to 1 or 2 percent, roughly halfway through the larval period. Once the flies emerged as adults, they were returned to a standard diet. The effects of the early protein restriction on lifespan were measurable in the adult flies.