Intermittent Fasting May Aid Weight Loss, Improve Hormones

• A recent study has found that intermittent fasting may positively affect the hormones in people with polycystic ovary syndrome (PCOS).
• These effects on hormones may help lead to greater weight loss.
• Weight loss has also been associated with improved PCOS symptoms.

According to the World Health Organization (WHO), PCOS affects 10–13% of females worldwide. This equals about 1 in 10 females of reproductive age having PCOS.

A recent study published in Nature Medicine found that intermittent fasting (IF) may positively affect hormones in people with PCOS, which, in turn, could contribute to weight loss.

A first-line treatment for PCOS is hormonal birth control. However, this medication can lead to negative side effects on mood, libido, and metabolism. It can also increase the risk of stroke in some people.

“We’re looking for other ways of lowering testosterone levels in these women,” Krista Varady, PhD, professor of kinesiology and nutrition at the University of Illinois Chicago, and an author of the study, said in a press release.

“One way is through weight loss. If someone loses around 5% of their body weight, they can actually help lower testosterone levels and sidestep any kind of drug intervention,” she continued.

Intermittent fasting, or time-restricted eating (TRE), has become a popular weight loss strategy. This method utilizes cycles of voluntary fasting followed by eating periods. It focuses more on when to eat than on what to eat.

“Intermittent fasting may improve adherence for some individuals compared to calorie or macro tracking, which can support weight loss and metabolic improvements. However, dietary quality remains foundational,” said Kristin Kirkpatrick, a registered dietitian at the Cleveland Clinic Department of Wellness & Preventive Medicine and President of KAK Consulting, who was not involved in the study.

The study analyzed 76 participants who were randomly assigned to one of three groups for 6 months:

• 6-hour TRE regimen with all meals eaten between 1:00–7:00 pm, with no calorie tracking
• calorie restriction, with a 25% daily energy restriction
• control group with no dietary restrictions

The primary factor the researchers were checking was the percentage change in body weight over 6 months.

Both the TRE group and the calorie-restriction group achieved significant weight loss by the end of 6 months.

Participants in the TRE group also showed changes in their testosterone and A1C levels. A1C levels are a risk marker for diabetes.

“Daily intermittent fasting could be an alternative to calorie counting for individuals with PCOS who are looking to lose weight. Both diets can also help with insulin resistance, which many people with PCOS have and which can put individuals at risk for diabetes,” Varady told Healthline.

“Intermittent fasting may also help lower testosterone levels in PCOS, which is important because testosterone is the culprit behind many PCOS symptoms,” she continued.

Varady added that intermittent fasting may be easier for many people to follow than calorie restriction. Many participants in the TRE group stated they would continue the diet.

Kirkpatrick said it’s important to establish a solid dietary foundation before focusing on fasting hours.

“From there, choose an eating window that fits your lifestyle and feels sustainable,” she said.

Varady suggested trying a 6 to 8-hour eating window that ends at least 1 hour before you go to bed. She recommended keeping a consistent eating window each day, as this will help your body to adjust to the new eating times more easily.

Of course, as with many diet and weight loss protocols, consistency is key. Limiting food intake to your eating window each day will yield the best results.

“While you don’t necessarily need to worry about diet quality while doing intermittent fasting — weight loss can happen regardless — it may benefit those with PCOS to also make dietary changes, including increasing non-starchy vegetables, lowering starchy carbs, and getting adequate protein,” said Varady.