Time-Restricted Fasting Potential Impacts on Fertility

Dietary patterns incorporating time-restricted fasting could lead to issues with fertility, according to new research from the University of East Anglia (UEA) published in the journal Proceedings of the Royal Society B Biological Sciences.

The study, conduced in zebrafish, looked at what happens when individuals are exposed to food during and after a period of fasting. They measured how males and females allocate resources to body maintenance versus production and maintenance of sperm and eggs, and the quality of the resulting offspring.

“What we found is that time-restricted fasting affects reproduction differently in males and females,” said Edward Ivimey-Cook, PhD, from the UEA School of Biological Sciences, in a statement. “Once the fish returned to their normal feeding schedule, females increased the number of offspring they produced at the cost of egg quality resulting in reduced quality of offspring. The quality of male sperm also decreased.”

While the study is limited to fish, the researchers said the findings highlight the importance of considering not just the effect of fasting on weight and health, but also on fertility.

“These findings underscore the importance of considering not just the effect of fasting on body maintenance but also on the production of eggs and sperm,” said Ivimey-Cook. “Importantly, some of the negative effects on eggs and sperm quality can be seen after the animals returned to their normal levels of food consumption following time-restricted fasting.

The researchers said more research is needed to understand how long it takes for sperm and egg quality to return back to normal after the period of fasting.