Weight loss may help improve several symptoms of PCOS

According to clinical guidelines in the U.K., 5% weight loss could lower testosterone levels and insulin resistance markers. Health experts recommend offering women with PCOS and overweight advice on lifestyle changes, typically involving weight loss through low-carbohydrate diets and exercise.

However, this study’s patient and public involvement (PPI) advisors shared that, in their experience, support for weight management was scarce. Evidence also indicates that encouragement for weight loss with no further support is mostly ineffective.

Medical News Today discussed this study with PCOS expert Dr. Ali Chappell, PhD, MS, RD, founder and CEO of Lilli Health, who was not involved in the review.

“When interventions focus on the root cause of weight gain — insulin resistance — PCOS symptoms are more likely to improve. Directly addressing insulin resistance is essential for achieving meaningful improvements in PCOS symptoms, including weight loss,” she explained.

MNT also discussed this research with Alyssa Pacheco, RD, of The PCOS Nutritionist Alyssa, who was also not involved with the study.

“PCOS is characterized by hormonal imbalances and metabolic disturbances, [I]nsulin resistance, chronic inflammation, estrogen imbalances, high cortisol, and gut dysbiosis can all make losing weight difficult,” she said.

Pacheco agreed that weight loss can help improve many PCOS symptoms.

“When someone loses weight, they can usually expect to see improvements in blood sugar and insulin levels, cholesterol levels, and testosterone levels. It also usually means they experience less cravings and fatigue while also having more regular periods.”
— Alyssa Pacheco, RD

Pacheco also shared that individuals with PCOS are at a disproportionately higher risk of eating disorders. This, she said, calls for greater caution when discussing weight loss interventions.

Prior research suggests that low-carbohydrate interventions or pharmacotherapy can promote weight loss and greater improvements in insulin resistance, glucose, and hemoglobin markers than metformin or no intervention.

However, the University of Oxford team noticed that no reviews had compared “the full range of weight loss interventions” regarding PCOS management.

Moreover, previous studies often lacked sufficient data to analyze clinically relevant symptoms and markers for PCOS management, including menstrual frequency, hirsutism, and free androgen index (FAI).

The study’s authors searched major medical databases for randomized controlled trials (RCTs) from inception until June 2024. They focused on RCTs of interventions to reduce weight in adults diagnosed with PCOS.

The experts compared:

• “usual care” of metformin, oral contraceptives, and standard advice,
• “minimal intervention” such as advice for losing weight without further support, or
• placebos.

They also analyzed trials that compared lower and higher-intensity weight loss interventions.

Primary outcomes

The review’s primary outcomes comprised of symptoms and biological markers of PCOS. They were chosen in consultation with clinicians with expertise in PCOS and 36 individuals with PCOS.

Included RCTs contained data that allowed weight change calculations and at least one symptom or bio marker of PCOS such as fasting insulin, fasting glucose, testosterone, FAI, menses frequency, acne, and hirsutism.

The study’s researchers started with 3,760 studies, paring their list down to 39. Over 1,500 people contributed data to the primary analyses, and over 2,300 contributed data to the secondary analyses.

The University of Oxford team reported: “For women with PCOS, our systematic review suggests weight loss interventions led to improvements in some important clinical features of PCOS.”

They noted decreases in fasting insulin, FAI, and HOMA-IR, an insulin resistance marker, along with increases in menstrual frequency.

“To our knowledge, this is the first review to show a clinically significant association in improvement in menstrual frequency with weight loss interventions, an important indicator of subsequent fertility and an important outcome for women,” the team also said.

However, evidence was inconclusive to establish an association between weight loss interventions and significant changes in fasting glucose, testosterone, hirsutism, and other markers.

MNT asked the interviewed experts which weight loss interventions seemed to work best.

Chappell shared that insulin-lowering methods are most effective in her experience: “Since insulin resistance is at the root of all PCOS symptoms, focusing on lifestyle changes that lower insulin levels helps reverse insulin resistance and leads to weight loss and improvements in other clinical symptoms. I call this a Low Insulin Lifestyle.”

“The most effective weight loss interventions are the ones that focus on treating the underlying root cause of why weight loss is difficult to begin with. I recommend eating balanced meals that include high fiber foods, protein, and healthy fats — this combination keeps blood sugar levels more stable and reduces cravings throughout the day,” Pacheco told MNT.

“Other lifestyle factors such as exercise, sleep, and stress can play a big role in insulin resistance and weight loss,” she added.

The study’s authors acknowledge several limitations to their review.

The main one, they noted, is “high statistical heterogeneity in the interventions, comparators, and outcomes….” They hope that more detailed meta-analysis will compare weight loss interventions.

Also, most of the studies analyzed were less than six months in duration. Thus, the long-term effects of the interventions are unknown.

This review does not reflect recent changes in weight management, such as total dietary replacements.

Chappell believes that the study’s findings highlight the importance of targeting insulin resistance to improve PCOS symptoms.

She also noted that while caloric restriction and other weight loss interventions resulted in modest weight loss, “they often failed to improve sex hormone levels and related PCOS symptoms such as hirsutism.”

“Insulin is the primary driver of androgen secretion and related PCOS symptoms, which is not influenced by calorie restriction alone,” she said.

Overall, the University of Oxford researchers feel that their work offers helpful considerations for individuals living with PCOS and overweight and their healthcare providers: “Weight loss interventions were associated with improvements in some important features of PCOS and should be considered as a routine treatment option for people with PCOS.”