Time-restricted feeding attenuates age-related cardiac decline in Drosophila

Hearts stiffen and falter with age in nearly every animal that has one, including the fruit fly. In humans, heart disease and heart failure are the leading cause of disability and death. Flies offer a useful model for studying this: they age in weeks rather than decades, and their genetics can be manipulated with precision.

Our earlier work in nocturnal mice had shown that time-restricted feeding could improve metabolic health, but whether it also protects the heart in old age was unknown. Here, flies were given identical food — one group could eat around the clock, the other only within a twelve-hour window, with nothing else differing between them. As the flies aged, those on the restricted eating window showed visibly better heart function, slept better, and displayed less of the deterioration typically seen at that stage of life.

The critical part of the experiment came next. When we disabled the flies' clock genes, the benefit disappeared entirely — the eating window stopped helping. This showed that the improvement wasn't simply a side effect of eating less, or some general benefit of rest; it worked specifically through the circadian clock. Follow-up experiments revealed that the clock and time-restricted feeding act together to make mitochondria more efficient and help proteins fold correctly — two processes whose breakdown is a major driver of aging. The study thus established that time-restricted feeding protects health through multiple molecular mechanisms, not just one.

Finding the same effect in an insect mattered too. Flies and mammals diverged on the evolutionary tree an enormous span of time ago, so a mechanism that holds in both is likely ancient and deeply conserved. It strengthens the case that meal timing is a fundamental feature of animal biology, not a quirk specific to laboratory mice.