Fasting — intermittent or otherwise — is an increasingly popular diet trend. The principal is simple: Restrict the time in which you eat to ensure an optimized metabolic rate for weight loss. However, a recent study on the effects of fasting on zebrafish has discovered some interesting results.
Time-restricted fasting may cause fertility problems.
Published in The Royal Society, the study examined how model organisms respond to food shortages. While the study performed experiments on zebrafish, the researchers involved in the study warned that the results may be revealing of how fasting affects the human body as well.
“Time-restricted fasting is an eating pattern where people limit their food consumption to certain hours of the day,” Alexei Maklakov, one of the study’s authors, told Science Daily. “It’s a popular health and fitness trend and people are doing it to lose weight and improve their health.
“But the way organisms respond to food shortages can affect the quality of eggs and sperm, and such effects could potentially continue after the end of the fasting period. We wanted to find out more about how these sorts of diets can affect fertility in a popular model organism.”
According to co-author Edward Ivimey-Cook, more research is needed.
“What we found is that time-restricted fasting affects reproduction differently in males and females,” he told Science Daily. “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.”
“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. 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. 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.”
Read the full study, “Fasting increases investment in soma upon refeeding at the cost of gamete quality in zebrafish,” here.
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