Time-restricted eating extends lifespan in male mice
Eating within a fixed daily window improves health in both male and female mice. But only males actually live longer because of it. The difference matters for how we think about intermittent fasting and aging.
Time-restricted feeding means consuming all food within a limited number of hours each day, typically aligned with the body’s internal clock. Researchers have tested whether this approach can slow aging, with mixed results across different studies.
A large study published in Nature Aging now provides a clearer picture. More than five hundred male and female mice were followed from early life until death. The researchers found that time-restricted feeding improved healthspan measures in mice of both sexes. But median lifespan increased only in males. In females, the same dietary pattern did not extend life.
What drives the sex difference
The male mice on time-restricted feeding showed better organ function and fewer signs of age-related decline compared to controls. They also lived measurably longer. Female mice improved on several health indicators but did not gain additional lifespan from the intervention.
Why this sex difference exists is not yet fully understood. Hormonal differences are a likely factor. So is the way the circadian rhythm, the body’s internal biological clock, functions differently in each sex. The circadian rhythm governs when the body expects food, when it performs repair, and when it prepares for activity. Disrupting or aligning with this rhythm has different consequences depending on sex.
What this means for human practice
Time-restricted eating is widely practiced for weight management and metabolic health. This study adds a new question: do the long-term aging effects also differ between men and women? The mechanisms involved, including circadian regulation and metabolic flexibility, are shared across mammals. Whether humans show the same sex-specific lifespan response remains to be tested. But the finding is a clear signal that sex must be factored into longevity research and dietary recommendations alike.