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A new study shows that women with PCOS who follow the keto diet may see improved fertility, weight loss, and lower testosterone. Anchiy/Getty Images
  • Between 8–13% of reproductive-aged women worldwide have polycystic ovary syndrome (PCOS).
  • There is no cure for PCOS, but treatment options exist for alleviating symptoms and lowering associated health risks.
  • A recent study shows that women with PCOS who follow the ketogenic diet may experience improvements in fertility, weight loss, and lower testosterone levels.

The World Health Organization (WHO) estimates that 8–13% of reproductive-aged women worldwide have polycystic ovary syndrome (PCOS) — a chronic condition that causes hormonal imbalances and may lead to infertility.

There is currently no cure for PCOS. Doctors utilize medications, fertility treatments, surgical options, and lifestyle changes — including diet and exercise — to help treat the condition’s symptoms and lower the associated health risks.

In a recent study, researchers from the Ministry of Health Malaysia in Kuala Lumpur, Malaysia, have found evidence suggesting women with PCOS who follow the ketogenic diet may see improvements in fertility, weight loss, and lower testosterone levels.

This study was recently published in the Journal of the Endocrine Society.

PCOS occurs when the ovaries over-secrete testosterone and other male sex hormones called androgens.

People with PCOS do not make enough of the hormones needed for ovulation, which can lead to irregular periods and infertility.

Between 70–80% of females of reproductive age with PCOS also have fertility issues.

Additionally, some women with PCOS will develop small cysts on their ovaries, also contributing to a hormone imbalance.

In addition to ovarian cysts, high androgen levels, irregular periods, and infertility, other symptoms of PCOS can include:

According to Dr. Karniza Khalid, a researcher at the Ministry of Health Malaysia in Kuala Lumpur, Malaysia, and lead author of this study, the effects of the keto diet on PCOS have been previously explored in clinical studies.

However, no systematic review has studied how the keto diet affects reproductive hormone levels.

“We decided to collate all the available evidence and synthesize the findings to allow for a robust conclusion and impact the clinical scene,” she told Medical News Today.

For the study, Dr. Khalid and her team analyzed data from seven clinical trials evaluating the effects of the keto diet in women with PCOS.

Scientists found women with PCOS who followed the keto diet for at least 45 days experienced significant weight loss, improved reproductive hormone levels, and lowered testosterone levels.

“PCOS is a complex hormonal condition — hyperandrogenism and reduced insulin sensitivity being one of the hallmark endocrinological features. Induction of physiological ketosis from keto diet will reduce the circulating insulin level and IGF-1, further suppressing the stimulus for adrenal and ovarian androgen production, hence limiting the level of circulating free androgen in the blood.”

— Dr. Karniza Khalid, lead study author

When a person eats carbohydrates, their digestive system breaks it down into sugar called glucose.

As glucose enters the bloodstream, the body’s blood sugar levels rise, causing the pancreas to produce insulin. Insulin helps remove the glucose from the bloodstream to feed it to the body’s cells.

If a person who is insulin resistant eats carbohydrates, the insulin the pancreas makes is not working properly. This ends up causing too much glucose to remain in the body’s bloodstream and the cells do not get the energy they need.

Previous studies have found that females with PCOS who follow a low carb diet may see improvements in:

There are a variety of low carb diets, with the keto diet being one of the most well-known.

The keto diet focuses on eating protein and healthy fats, and very little carbohydrates. This ultimately uses up the body’s sugar reserves, causing it to start breaking down body fat for energy.

This is not the first study to examine the keto diet’s effect on PCOS. A study in February 2020 found the keto diet to be a “valuable non-pharmacological treatment” for PCOS.

Additionally, previous studies suggest low carb diets may help with PCOS-related infertility issues. A study published in November 2021 found a low carb diet to be an “effective intervention” for improving fertility health in women with PCOS.

Another study in October 2022 found a very low calorie keto diet may help improve metabolic and ovulatory dysfunction in women with PCOS.

The exact cause of PCOS is still unknown, but previous research shows risk factors for the condition may include:

Past studies show anywhere from 35–80% of women with PCOS also have insulin resistance, meaning their body does sufficiently use insulin, the hormone that regulates glucose.

Insulin resistance can affect fertility as it causes higher levels of inflammation. It can also lead to higher testosterone levels in the body, which interferes with regular ovulation.

Additionally, as insulin is the hormone responsible for telling the body when to store fat, high levels lead to weight gain, which could also cause fertility issues.

Insulin resistance places women with PCOS at a higher risk for developing diabetes, which can also affect fertility.

MNT also discussed this study with Dr. G. Thomas Ruiz, OB-GYN lead at MemorialCare Orange Coast Medical Center in Fountain Valley, CA.

Dr. Ruiz said he was not surprised by this study’s findings because insulin resistance is common with PCOS.

“I have been telling my patients to go on low carb diets for years,” Dr. Ruiz continued. “My preference is the Mediterranean diet, (but) I have a preference for any diet which is low carb where you do not see increased insulin secretion.”

“One of the hallmarks of the keto diet is high fat, high protein, but almost no carbs — a limited number of carbs. And it’s the simple carbs that create high glucose levels. If you can control their insulin levels and get them to drop, (women with PCOS) actually may start to ovulate spontaneously and start to reverse changes that occur because of hyperinsulinemia, including decreasing testosterone levels.”

— Dr. G. Thomas Ruiz, OB-GYN

Still, the keto diet is not for everyone, particularly pregnant people, individuals with certain health conditions like hypothyroidism, or those with an eating disorder.

“(A) few parameters should come into play when planning: age, baseline BMI, gender, baseline health status — (the) presence of kidney and liver impairments — and gut health,” Dr. Khalid noted.

If you live with PCOS and are unsure whether the keto diet is right for you, Dr. Khalid recommends discussing any dietary changes with a gynecologist, endocrinologist, and dietitian.