Did you know that Polycystic Ovarian Syndrome (PCOS) affects 1 in 5 women in Australia during their reproductive years?  (Healthdirect, 2020). PCOS can disrupt menstruation, harm fertility, lead to “cysts” on a woman’s ovaries, and lead to skin and hair changes in affected women (Healthdirect, 2020), yet surprisingly up to 70% of women go undiagnosed!

The good news is, for those who suffer from this condition, there are potential treatments for many of the accompanying symptoms. This can range from medications, to surgical or cosmetic treatments, to lifestyle factors. One form of treatment is diet…in fact, the use of the ketogenic diet to improve symptoms of PCOS has some very interesting pros and cons… So before you try it for yourself, let’s dive into the research!

Read more about what to eat for PCOS.

The keto diet requires severely restricting carbohydrate intake, and focusing on a diet rich in fats, with a moderate intake of protein.


1. May improve insulin resistance.

Women with PCOS can have high insulin levels. Insulin is a hormone produced in your pancreas to help your body turn glucose (sugar) into energy (Whelan, 2019). If you’re insulin resistant, this can mean your body is pumping out too much insulin to try to keep your blood sugar levels stable, however this can be problematic (Whelan, 2019). Excess insulin means your ovaries produce more androgens (“male” hormones) like testosterone

(Whelan, 2019), and can also lead to weight gain, or make it harder to lose weight.

Refined carbohydrates, like starchy and sugary foods, have been shown to worsen insulin resistance. Which is where the keto diet comes in…

Keto diet for PCOS

Studies have shown that obese women with PCOS and insulin resistance benefitted from following a low carb diet such as keto, with blood sugar levels and insulin production falling significantly (Groves, 2019) (Paoli et. al, 2020). This means your body produces far less androgens, and your blood glucose and weight are much more stable. So a win for keto!

Read more about nutrition and insulin resistance here.

2. May improve hormonal imbalance.

PCOS is often accompanied by hormone imbalance, particularly elevated levels of androgens (also known as testosterone) which is responsible for some of the symptoms like acne, hair loss and hair growth associated with PCOS (Mavropoulos et. al, 2005). However, the keto diet has been found to really help with rebalancing women’s reproductive hormones.

In a six-month study, women who followed the keto diet experienced a significant decrease in free testosterone, less production of androgens, an improvement in LH to FSH ratio, and improved fertility – with two women who were previously infertile actually falling pregnant (Mavropoulos et. al, 2005).

The rebalancing of reproductive  hormones is hugely important for fertility, reducing inflammation, and preventing excess weight gain for women with PCOS.

Read more about the impact of the keto diet on fertility and pregnancy

PCOS and ketogenic diet

3. Weight loss.

As we’ve touched on, the keto diet can help with weight loss for women with PCOS, by improving insulin resistance and hormonal imbalance (Mavropoulos et. al, 2005).

Studies found on average, women with PCOS who followed the ketogenic diet saw a 12% decrease in body weight, with little impact on their lean body mass (Mavropoulos et. al, 2005), suggesting the weight loss was primarily fat loss. 

Though further research is needed to determine if this fat loss was due to the keto diet, or from restricting carbohydrates.

Keto diet for PCOS

4. Can help with  inflammation.

The keto diet also improved inflammation in women with PCOS (Paoli et. al, 2020). Just 12 weeks of following a keto diet saw women experience significantly improved inflammatory markers (Paoli et. al, 2020), largely linked to their improved insulin resistance, hormone balance, cholesterol and triglycerides (Paoli et. al, 2020). These findings imply that the keto diet may potentially be really helpful in reducing all the hormonal anomalies linked to PCOS!

PCOS and ketogenic diet

However, it’s not all sunshine and rainbows… 

The keto diet also has some serious cons when it comes to treating PCOS.


1. Inadequate fibre.

The keto diet is so restrictive on carbohydrate intake, that it becomes virtually impossible to get enough fibre into your diet. Fibre is so important for digestion, gut health, bowel movements and weight balance – so this can be a real issue.

High fibre foods, such as cruciferous vegetables, leafy greens, beans, lentils, sweet potato and whole grains, have actually been found to improve insulin resistance by slowing down your digestion, and therefore reducing the impact of glucose on your blood sugar levels (Whelan, 2019). Basically, high-fibre foods help prevent that spike in energy you get after eating a really high-energy or sugary food, which is almost always accompanied by a major crash in energy shortly afterwards. 

Fibre also helps you feel fuller for longer, which can assist with weight loss for women with PCOS (Groves, 2019). In fact, studies have shown that a high fibre intake resulted in lower insulin resistance, body fat and stomach fat in women with PCOS (Groves, 2019).

So these foods are really important and beneficial for women with PCOS, yet aren’t really “allowed” as part of a keto diet…

Keto diet for PCOS

2. Poor sustainability.

One of the major issues with the keto diet is its sustainability in the long term. It is such a restrictive diet, that many people find it really difficult to stick to (Preiato, 2019).

Think about going out for a meal with friends or family… it can be really challenging to find something “keto-friendly” due to the strict restrictions on carbohydrate intake, meaning the diet can actually impact your socialising, and even cause anxiety or stress around food (Preiato, 2019) – not cool!

This restriction and deprivation can also lead to a negative relationship with food.

There are very few studies surrounding the potential benefits of following the keto diet long-term, with many suggestions that it could actually be harmful to the health of women with PCOS if adhered to for too long (Preiato, 2019). So this is a very important consideration when beginning a keto diet!

Ketogenic Diet for PCOS

3. Negative impact on gut health.

As we’ve discussed, the keto diet is low in fibre, meaning it can be very damaging to gut health (Link, 2019). The keto diet eliminates (or severely restricts) foods like  fruits, starchy vegetables, grains and legumes (Link, 2019) – all of which are high in fibre, and fantastic for your gut health!

High fibre and diverse plant intake has been shown to improve gut health, by feeding the good bacteria and helping to balance your gut microbiome – in fact, it even helps prevent stomach ulcers and other digestive issues (Link, 2019).

Studies have shown the potential of a keto diet to impact the composition of your gut bacteria,with one six-month study showing a keto diet led to increased inflammation in the gut, and the not-so-beneficial gut bacteria (Link, 2019).

The use of artificial sweeteners to replace natural sugars in the keto diet is also very damaging for gut health (Mancin et. al, 2019). Several studies have shown that artificial sweeteners disrupt the structure, function and health of the gut microbiome and mucosa (Mancin et. al, 2019).

PCOS and ketogenic diet

Considering gut health is vital for digestion, immunity, mental health, and so many other  things, this is a big con indeed! And with emerging research suggesting a potential role of the gut microbiota and probiotics in the management of PCOS, this is certainly a key area of concern! (Ahmadi et al., 2017).

4. Disordered eating

I cannot tell you how many women with PCOS have trialled a ketogenic diet or a very low carbohydrate diet and perhaps lost a few kilos, have ended up with your relationship with food in absolute tatters.

At the end of the day, we eat multiple times each day, every day, having a negative or troubled relationship with food is difficult to manage, unpack and resolve and often isn’t worth the benefits you got from following this restrictive dietary pattern.

We also know women with PCOS in general struggle more so with disordered eating, in fact some literature cites that the rates of eating disorders are significantly higher than the general population (Lee et al., 2019).

Considering the delicate balance between pros and cons, it’s always best to seek advice and guidance from an accredited practicing dietitian to help you make the diet and lifestyle choices that best suit your needs!

Introducing…The PCOS Project

This self-paced online course has been developed to highlight the role of diet and nutrition in managing your PCOS symptoms and taking control of the rollercoaster that is PCOS with 10 comprehensive PCOS-specific nutrition lessons. We also include BONUS PCOS-friendly 7-day meal plans and recipes! Check it out ?

What you’ll get inside The PCOS Project:

  • Over 10 comprehensive PCOS-specific nutrition lessons designed & delivered by expert reproductive health dietitian & nutritionist
  • Learn exactly what bloodwork you need to monitor your PCOS today and in the long-term too!
  • Take control of insulin resistance and stubborn weight using the insulin resistance lesson & comprehensive workbook
  • Our strategies to lower androgens driving those pesky pimples & chin hairs!
  • Understand your menstrual cycle, the ways you can track it, what the “red flags” are for more help and how to nourish yourself for more regular periods!
  • PLUS: supplementation considerations for PCOS (note: does not include personalised supplementary advice), mood & food for mental health, anti-inflammatory eating for PCOSoptimising gut health & how to build a PCOS-friendly meal

BONUS: PCOS-friendly done-for-you 7-day meal plans with recipes AND additional recipe resources!
You will get 2 YEARS to access this incredible VAULT of expertly crafted & delivered PCOS education.

Looking for more guidance on how to best meet your nutrition needs, or manage your PCOS symptoms? Apply to work with me one-on-one today and let’s develop a tailored plan for your goals!This blog was co-written by Emily Smith, a Nutrition and Dietetics student at The University of Sydney. You can find Emily on Instagram @emilygracehealth and on LinkedIn.

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