Kilos are not the only thing that intermittent fasting will help you shed. A new study shows that the wildly popular weight-loss method could also inhibit hair growth. Here is all you need to know. What is intermittent fasting? Intermittent fasting is essentially a time-restricted diet, where the day’s calorie requirements are consumed over eight to twelve hours, with participants fasting for the rest of the day. Studies that tracked participants on such diets for short periods — three months to a year — have shown benefits such as weight loss, increased insulin sensitivity, and better control of diabetes. The reported benefits of intermittent fasting have made it wildly popular globally. More than 12% of all respondents went on this diet, according to a 2023 survey carried out in the United States. (‘2023 Food and Health Survey’ by the International Food Council). What are the cons of intermittent fasting? With intermittent fasting becoming one of the biggest fad diets on the planet, researchers have attempted to better analyse its outcomes. Not all of the results have been positive. Earlier this year, data presented at a conference organised by the American Heart Association found that people who ate all of their food in less than eight hours per day had a 91% higher risk of death due to cardiovascular disease. Researchers analysed more than 20,000 US adults, and from a database for eight to 17 years to arrive at these results. Other studies have linked intermittent fasting to a disruption in one’s sleep cycle, which comes with its own set of poor outcomes, as well as a host of gastric issues. And what about hair loss? The recent study, published on Friday (December 13) in the journal Cell, is among the first to provide evidence of a link between intermittent fasting and hair loss. “.Commonly used intermittent fasting regimens inhibit hair follicle regeneration by selectively inducing apoptosis [programmed cell death] in activated hair follicle stem cells (HFSCs).,” the study titled “Intermittent fasting triggers interorgan communication to suppress hair follicle regeneration” says. Researchers found that mice subjected to intermittent fasting regimes showed slower hair regeneration compared to mice with access to food all the time. Based on a small clinical trial, they also found similar results in humans but cautioned that this is likely to be less severe since humans have a much slower metabolic rate and different hair growth patterns compared to mice. How can intermittent fasting lead to hair loss? The researchers found that intermittent fasting inhibited hair growth because HFSCs are unable to cope with the oxidative stress associated with switching from using glucose to fat, as happens during intermittent fasting when the body burns fat for energy. (This is also why intermittent fasting helps lose weight). HFSCs go through phases of activity and dormancy, and hair regrowth depends on these cells becoming active. While the control mice’s HFSCs (those who had constant access to food) became activated after being shaved and remained active till their hair had regrown, the mice which were intermittently fasting saw their activated HFSCs undergo apoptosis during extended fasting periods. “During fasting, adipose tissue starts to release free fatty acids, and these fatty acids enter the HFSCs that were recently activated, but these stem cells don't have the right machinery to use them,” Bing Zhang, senior author and stem cell biologist of Westlake University in Zhejiang, China, told Cell Press. That said, larger studies are required for a greater understanding of the process. “The human population is very heterogeneous, so the effects might be different for different people,” Zhang said.
