Polycystic ovary syndrome (PCOS) is the most common hormonal disorder among women aged between 18–44 and affects 1 in 5 women of reproductive age (1). The exact causes of PCOS are unknown but are thought to be a result of the complex interactions between genetic and environmental factors. Several genes (such as insulin resistance and inflammatory genes) and environmental factors (such as exercise and diet) have been associated with PCOS (2). PCOS affects women of all races and ethnicities. There is no cure for PCOS, however, the symptoms can be managed (3). Emerging evidence suggests intermittent fasting (IF) has beneficial effects on the symptoms of PCOS.

Figure above shows a polycystic ovary in comparison to a normal ovary. A polycystic ovary has an enlarged appearance with multiple follicles (cysts).to a normal ovary. A polycystic ovary has an enlarged appearance with multiple follicles (cysts).

The symptoms of PCOS may include central obesity, menstrual and ovulatory irregularities (an ovulation/oligo-ovulation), and expression of hyperandrogenaemia (a state of too many androgens/male hormone expression) (4). Physical signs may include increased facial and body hair growth, acne, and male pattern baldness.


According to the National Institute for Health and Care Excellence (NICE) guidelines, two of the following criteria must be met for the diagnosis of PCOS (4):

No alt text provided for this image

Polycystic ovaries are defined by the presence of 12 or more follicles which are between 2–9 mm in diameter in one or both ovaries. 

Women with PCOS are at an increased risk of conditions such as cardiovascular disease, type 2 diabetes, cancer, sleep apnoea, dementia, depression, and anxiety. Metabolic disturbance in PCOS is associated with increased adiposity, and clinically worsened menstrual cyclicity, ovulation rates, fertility, maternal and neonatal outcomes (5). In several cases, women with PCOS show infertility or subfertility and other metabolic alterations, such as insulin resistance, hyperinsulinemia (higher levels of insulin than normal), and obesity (6). Due to these risks and comorbidities, PCOS is associated with a high economic burden, of which infertility is a major contributing factor (7). Women with PCOS also have higher rates of hospitalisations than women without PCOS (7).

Challenges in diagnosing PCOS

It takes 2–3 years to be diagnosed with PCOS. A reason for a delayed diagnosis is that symptoms of PCOS vary in severity and presentation. The symptoms of PCOS are non-specific, resulting in delayed diagnosis. A delayed diagnosis leads to patients not receiving treatment for their PCOS which could consequently further exacerbate their symptoms. Appropriate diagnostic criteria are required to ensure PCOS is not missed and women get treated as soon as possible.

Most definitions of PCOS include women of reproductive age, however, these fail to recognise PCOS in teenagers and menopausal women. Furthermore, some women report being unaware of the symptoms of PCOS until they are diagnosed. Going forward, it is important to recognise the differences and similarities between women with PCOS when making a diagnosis. It is also important to raise awareness about the symptoms of PCOS, especially among women of ethnic minorities due to their language and access barriers.

Insulin resistance in PCOS

Emerging evidence and recent studies show insulin resistance to be significantly associated with PCOS. Insulin resistance is a common presentation among patients with PCOS, affecting 65–70% of women with PCOS. It was previously thought that insulin resistance only affected obese women, however, recent evidence suggests insulin resistance is independent of body weight (8). Since up to 60% of women with PCOS are overweight or obese, dietary and exercise interventions have become the primary management (8)

Intermittent fasting

IF is an umbrella term for a time‑restricted feeding period. Various fasting methods exist and the fasting/eating window can be based on a woman’s personal goals. It is recommended that you speak to your healthcare professional when deciding to fast. The 16/8 method (generally recommended) involves fasting for 16 hours of the day and consuming meals during an 8‑hour window. The goal of fasting is to prevent rising insulin levels and maintain low levels of free insulin in the blood. The image below illustrates the timeline of bodily changes by hours fasted.

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A recent study conducted by Li and colleagues, 2021, investigated time-restricted feeding in eighteen women with PCOS. The 6‑week trial followed the journey of women who fasted using the 16/8 method, without caloric restriction or changing their diet. The study showed significant differences in body weight, body fat percentage and insulin resistance. This study showed the possible benefits of IF in women suffering from PCOS (8).

It is important to consider that the study was performed on Chinese women and used a small study sample, therefore, making the study less representative of women across the world. Despite its limitations, this is a positive start for women struggling with PCOS. IF shows beneficial changes to PCOS symptoms. Due to positive changes were seen in Li et al’s research, IF may have the potential to reverse symptoms of PCOS. However, it is too early to say whether this is possible and more long‑term research must be conducted.

Existing data show that insulin resistance can have detrimental effects on the body in women with PCOS. Current treatments attempt to treat the symptoms of PCOS but are failing to recognise the root cause, which is insulin resistance.

Petition to increase funding

A recent petition to increase funding for research into PCOS was successful in getting a response from the UK government. This petition was created by a woman who suffered from PCOS and it took an astonishing 7½ years to diagnose her with PCOS. The government responded to the petition in August 2020, receiving over 100,000 signatures. The government claims to have awarded £6.60 million into PCOS research to the National Institute for Health Research (NIHR) in 2020. NIHR published a letter in 2018 recognising there is an underestimated problem in primary care with PCOS. Although this is one small step in the right direction, there is significant underreporting of PCOS in primary care and no ground-breaking research about PCOS has been published by the NIHR since this letter. 

Challenges in research

Current evidence is not well established for lifestyle management for women with PCOS. The effectiveness of specific lifestyle changes, such as diet and exercise, are also not well understood for women-centred outcomes. Many studies informing the evidence base are underpowered and report a high risk of bias, particularly from high attrition (3). Considering that PCOS has a high burden on quality of life, this needs to be resolved urgently.

Another major issue in researching PCOS is that they often require women to stop taking medications, especially contraceptives and insulin-sensitising drugs. Participants do not want to stop taking their medication, which has the risk to further exacerbate their symptoms and prevent study participation. Women are already massively underrepresented in clinical trials, but if there are barriers to female participation in trials investigating women’s health concerns, this deepens the existing knowledge gap and stalls treatments and solutions.

The next steps towards in improving the quality of life of women struggling with PCOS is more research, attention, and funding. We require further research on the causes of PCOS and better diagnostic criteria. Raising awareness through governmental and healthcare policies, as well as clinical research, on behalf of all ages and ethnicities would reduce diagnostic delay. More funding and research surrounding PCOS would also contribute to understanding the aetiology, pathophysiology, and potential treatments (both medical interventions and lifestyle modifications) for this condition. This is vital to enable women to access adequate and personalised medical attention and treatment from healthcare professionals, leading to a better quality of life and a reduced disease burden. It is undeniable that there is still plenty of ground to cover; talking about PCOS and highlighting the areas of concern is only the first step.

Useful links for more information

Information on intermittent fasting and its benefits:

  •  Dr Berg’s Youtube Channel
  •  Dr Jason Fung’s Youtube Channel

Information on PCOS and intermittent fasting:

  • Dr Nadia Pateguana’s website (Naturopathic doctor who also experienced PCOS and has published a book along with Dr Fung “The PCOS Plan: Prevent and Reverse Polycystic Ovary Syndrome through Diet and Fasting”): https://www.doctornadia.com/

More on PCOS and management:


  1. Teede, H., Deeks, A. and Moran, L. (2010) ‘Polycystic ovary syndrome: a complex condition with psychological, reproductive and metabolic manifestations that impacts on health across the lifespan’, BMC Medicine, 8, p. 41. doi: 10.1186/1741-7015-8-41.
  2. Stracquadanio, M. and Ciotta, L. (2015) Metabolic Aspects of PCOS. Cham: Springer International Publishing. doi: 10.1007/978-3-319-16760-2.
  3. Polycystic ovary syndrome | Office on Women’s Health (no date). Available at: https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome (Accessed: 5 August 2021).
  4.  Polycystic ovary syndrome | Health topics A to Z | CKS | NICE (no date). Available at: https://cks.nice.org.uk/topics/polycystic-ovary-syndrome/ (Accessed: 5 August 2021).
  5. Arentz, S. et al. (2021) ‘Perceptions and experiences of lifestyle interventions in women with polycystic ovary syndrome (PCOS), as a management strategy for symptoms of PCOS’, BMC Women’s Health, 21(1), p. 107. doi: 10.1186/s12905-021-01252-1.
  6. Chiofalo, B. et al. (2017) ‘Fasting as possible complementary approach for polycystic ovary syndrome: Hope or hype?’, Medical Hypotheses, 105, pp. 1–3. doi: 10.1016/j.mehy.2017.06.013.
  7. Rajora, P. et al. (no date) ‘A targeted literature review of the economic burden associated with polycystic ovary syndrome’, p. 1.
  8. Li, C. et al. (2021) ‘Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome’, Journal of Translational Medicine, 19(1), p. 148. doi: 10.1186/s12967-021-02817-2.
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