For years, people who had polycystic ovary syndrome and were also overweight were told that their symptoms would improve if they lost weight via a restrictive diet. In 2018, a leading group of PCOS experts recommended that overweight or obese women with the hormonal disorder consider reducing their caloric intake by up to 750 calories a day. That guidance helped to spawn questionable diet programs on social media, and reinforced an impression among people with PCOS that if only they could successfully alter their diets, they would feel better.
But the recommendations were not based on robust PCOS studies, and researchers now say that there is no solid evidence to suggest that a restrictive diet in the long-term has any significant impact on PCOS symptoms. Dieting rarely leads to sustained weight loss for anyone, and for people with PCOS, losing weight is particularly difficult. Beyond that, the link between sustained weight loss and improved symptoms is not very clear or well-established, said Julie Duffy Dillon, a registered dietitian specializing in PCOS care.
In 2023, the same group, called the International PCOS Network, revised its guidance based on a new analysis of the research and dropped all references to caloric restriction. The group now recommends that people with PCOS maintain an “overall balanced and healthy dietary composition” similar to the Mediterranean diet, which is associated with a reduced risk of the health issues that are linked to the disorder, like cardiovascular disease and diabetes. It’s not known whether eating this way might improve symptoms of PCOS.
The changes in the guidelines reflect “the PCOS literature and the lived experience of people with the condition,” said Dr. Helena Teede, an endocrinologist at Monash Health in Australia and lead author of the 2023 guidelines. “It’s no longer about blaming people or stigmatizing them, or suggesting that it’s their personal behavioral failure that they have higher weight.”
What is PCOS?
PCOS is a hormonal disorder that affects as many as five million women in the United States. It’s characterized by irregular periods, infertility, excessive facial hair growth, acne and scalp hair loss — symptoms that are common with other health conditions, too, making diagnosis tricky. People with PCOS usually ovulate less than once a month and often also have higher levels of androgens (male sex hormones) or multiple underdeveloped follicles on their ovaries (not, as the name suggests, cysts) or both.
Typically, when a woman is experiencing symptoms, a doctor will either scan the ovaries to look for those follicles or draw blood to test hormone levels. There is no cure for PCOS; the first line of treatment is often some form of birth control to help regulate the menstrual cycle.
Though PCOS is usually framed as a reproductive issue, it can also affect metabolic health — including blood sugar, blood pressure and cholesterol levels. People with PCOS often have chronic inflammation, which occurs when the immune system is overstimulated for extended periods of time. And they are at a higher risk of developing cardiovascular disease, endometrial cancer and diabetes, said Dr. Heather Huddleston, director of the PCOS Clinic and research program at the University of California, San Francisco.
The condition has also been associated with an increased risk of mental health issues, like depression, anxiety, suicide attempts and eating disorders.
The body-weight connection
The relationship between PCOS and weight is complex; the condition is strongly associated with obesity. Someone with PCOS is predisposed to gain weight and, as they do, their symptoms might worsen, said Dr. Anuja Dokras, director of the Penn Polycystic Ovary Syndrome Center at the University of Pennsylvania and a co-author of the 2023 guidelines. “It’s a bidirectional relationship,” she said, but “we don’t understand why it is that they tend to gain weight.”
The 2023 guidelines also noted that obesity rates among people with PCOS vary in different parts of the world. And, Dr. Dokras said, not everybody with obesity has PCOS.
Some studies have shown that weight loss via lifestyle changes might improve some hormonal and metabolic symptoms of PCOS, Dr. Teede said, but “the evidence around fertility is challenging.”
Very few studies have measured changes in ovulation and pregnancy rates. “One of our biggest research questions is how much weight loss, over how much time, and then how much stability of that weight we need for the body’s reproductive system to kick back in,” she added.
The most convincing sign that weight loss might be associated with improved ovulation and pregnancy rates comes from recent studies that have looked at the outcomes of bariatric surgery among obese women with and without PCOS, Dr. Dokras said. Those data show that, after surgical intervention and drastic weight reduction, those with PCOS “start having very regular periods and the male hormone levels also drop.” Research to study whether weight loss drugs like Ozempic can improve symptoms for PCOS patient is still ongoing.
But many women with PCOS have insulin resistance — when the body does not effectively use the insulin it creates, leading to elevated levels of blood sugar. This can exacerbate some symptoms, including weight gain, and also make weight loss particularly difficult, Dr. Huddleston said.
And Ms. Dillon said that the old advice to restrict calories in order to lose weight has been especially troubling given the higher rates of eating disorders among people with PCOS. Anecdotally, she said she has seen the lasting harm of the advice in many of her patients.
When people try diets “and inevitably fail because they don’t work for most people, then they take ownership of it, like, ‘Well, that’s my fault,’” Ms. Dillon said. “So then they don’t seek health care anymore. It’s not uncommon for people with PCOS to meet with me and tell me I’m the first person they’ve seen in 10 years.”
By that point, she added, “they have lots of different health concerns, like diabetes and high cholesterol, but they also are ashamed and depressed and anxious.”
