Polycystic ovary syndrome (PCOS) affects up to 18% of all women of childbearing age. This condition occurs when a woman’s body produces too much of a group of hormones called androgens, primarily testosterone. It can lead to irregular menstruation, obesity, and even infertility.
The first line of treatment is usually hormonal birth control, said Krista Varady, a professor of nutrition at UIC. But it can have negative side effects on mood, sex drive and metabolism, and may even increase the risk of stroke in some people, Varady said.
We are looking for other ways to lower testosterone levels in these women. One way is weight loss. Losing about 5% of your body weight can actually lower your testosterone levels and avoid any kind of drug intervention. ”
Krista Varady, UIC Professor of Nutrition
A new study led by Varady examined how one weight loss method, intermittent fasting, affects hormones and symptoms in PCOS patients. Published in natural medicinestudies have shown that restricting meals to no more than six hours a day reduced testosterone without negatively impacting female hormones. The study also showed that weight loss due to calorie counting decreased testosterone.
But some critics of intermittent fasting argue that the diet disrupts female hormones, Varady said.
“There’s a particular feeling that intermittent fasting is really bad for women.” This is not true, she said. “This study, and several others published by our lab and others, show that intermittent fasting can actually improve female hormone levels, especially in women with PCOS.”
Varady and colleagues studied a type of intermittent fasting called time-restricted eating. With this method, you only eat for a set period of 6 or 8 hours each day. Fast for the remaining 18 or 16 hours with non-calorie drinks and water until the next day.
Simply put, this strategy helps people eat less, Varady said. So is calorie counting, a method Varady and her colleagues tested alongside intermittent fasting in their research. But intermittent fasting had some additional benefits.
“It’s a way to reduce your energy intake without doing super complicated calorie counting,” she said of intermittent fasting. Previous research by Varady and his colleagues showed that eating only during 8-hour windows can save about 300 to 500 calories per day.
In addition to obesity and insulin resistance, which increase the risk of diabetes and heart disease, PCOS can cause ovarian cysts, acne, and facial hair growth.
Researchers tested how time-restricted eating and calorie counting from 1pm to 7pm daily differed in their results after six months in a group of 76 premenopausal women with PCOS. Both diet plans ended up reducing participants’ intake by about 200 calories per day, leading to an average weight loss of about 10 pounds over six months, the researchers said.
Both groups also experienced a decrease in testosterone levels. But simply eating for a limited time reduces the free androgen index (the ratio of testosterone to the proteins that transport it through the bloodstream), a marker of how much active testosterone is reaching the body’s tissues. Varady said his A1C levels, a risk marker for diabetes, also improved.
Although intermittent fasting did not reduce other PCOS symptoms, such as irregular menstrual periods, Dr. Varady suggested that these symptoms may improve with longer diet periods and significant weight loss.
About 80% of participants in the time-restricted eating group said they planned to stick with the diet, Varady said.
The study was a team effort involving professors of nutrition in the Department of Kinesiology and Nutrition in the School of Applied Health Sciences. Sofia Cienfuegos designed and ran the study with Varady, and Kelsey Gabel, Lisa Tushing-Humphries and Vanessa Oddo also assisted.
“We all have a strong interest in women’s health, and we designed this together and ran it together,” Varady said. “This was one of the largest collaborations we have ever had in the nutrition sector.”
Other UIC authors on the study include Sarah Corapi, Mary Claire Lanchey, Jody Lyons, Maria Alonso de Leon, Vasiliki Pavlou and Mark Ezpeleta from the College of Applied Health Sciences. Julian Sanchez of the School of Medicine. Shuhao Lin, formerly of UIC and currently at Mayo Clinic.
sauce:
University of Illinois at Chicago
Reference magazines:
Corapi, S. others. (2026). Time-restricted eating for weight control in women with polycystic ovary syndrome: A randomized controlled trial. natural medicine. DOI: 10.1038/s41591-026-04316-7. https://www.nature.com/articles/s41591-026-04316-7
