Ketogenic Diet and PCOS: Is Keto Good for PCOS?

The ketogenic diet known as keto has grown in popularity over the last few years with “keto” being the most Googled food-related topic globally in 2020. Naturally, this has led to curiosity about whether this low-carb diet could help improve symptoms of PCOS. But what does the evidence say? Keep reading for more on PCOS and keto diet.

What is the ketogenic diet?

The ketogenic diet consists of a high fat (around 80%) and low carbohydrate intake. The main source of fats can include; butter, avocados, nuts, seeds, oil etc. Fat consumption is encouraged from unsaturated fats. Unsaturated fats are found in avocados, fish, nuts and seeds for example. The rest of the diet comprises a small number of carbohydrates avoiding high-carbohydrate foods such as starchy grains.

The aim of a ketogenic diet is to send the body into “ketosis”. Ketosis is when the body burns fat instead of carbohydrates as the main fuel source. When we don’t consume carbohydrates, the liver breaks down fat stores to produce energy. This energy is in the form of molecules called “ketones”.

Whilst popular, the ketogenic diet is commonly difficult to follow due to its restrictive nature. But what about the effect of keto on PCOS?

Keto diet and PCOS: what does the evidence say?

It is important to mention that data on the keto diet for PCOS is lacking. In particular, data is limited to the short term and studies are small. The theory behind keto for PCOS is that a low carbohydrate diet may help with insulin resistance; a common driver and symptom of PCOS.

One study investigated the impact of diet on PCOS symptoms on eleven people with PCOS. Carbohydrate intake was limited to 20g a day for a 6-month period. Over this 24-week period, improved LH/FSH ratio, and improved insulin levels were seen. Only five people completed the study, which may indicate the challenging nature of the keto diet.

A study was conducted on 20 PCOS participants, of whom only 18 completed the 3-month study due to the restrictive nature of the diet. For those who did complete the study, improvements in the menstrual cycle, liver function, blood glucose levels and body weight were found. Interestingly, similarly to the study above, only fourteen people completed the study.

Whilst the results appear promising, it is important to point out that the studies were carried out on a very small number of participants over short periods of time. Further research on larger samples of individuals over longer periods of time is required to deem results conclusive.

5 things to consider before trying keto for PCOS

At The PCOS Collective, we respect body autonomy and the right to choose what you do with your body. But, it is important to understand the pros and cons of certain ways of eating to ensure you have all of the evidence before you make a decision. Here are 5 things to consider before trying a ketogenic diet for PCOS:

Sustainability of the diet

Is the keto diet sustainable for you? Due to its highly restrictive nature, a ketogenic diet can be hard to follow. Whilst some evidence from short-term, small-scale studies suggests it may be helpful in symptom management there are non-restrictive ways of managing symptoms including enjoying a varied diet without food restrictions.

A common symptom of PCOS is carbohydrate cravings, likely because of the insulin resistance associated with PCOS. Because of the drastic reduction of carbohydrate consumption characteristic of a keto diet, carb cravings are likely to be increased further. This makes the diet even more difficult to follow.

Impact on gut health

Because a ketogenic diet limits the amount of carboydrates you consume, you may not get enough fibre from fruits, vegetables, wholegrains, beans and lentils. Fibre can be important in PCOS management because not only does fibre help to keep you fuller for longer, but it can also improve gut health and aid in balancing blood sugar levels.

Long-term effects may be damaging

A meta-analysis looking at over 100 peer-reviewed studies on ketogenic diets identified the long-term effects of the keto diet. They found that people following a keto diet have a significantly increased risk of developing heart disease, LDL cholesterol build-up, kidney failure, diabetes and even cancer.

Potential side effects

There are many side effects of the keto diet from mild to serious. This may include “keto flu” which includes symtoms like an upset stomach, headache and fatigue.

Other side effects of a keto diet include bad breath, constipation (likely from the lack of fibre), insomnia, dehyration, low bone density, bone fractures, high cholestrol and kidney stones.

Unsuitable for pregnant people or those trying to get pregnant

The meta-analysis study also found that keto diets are particularly unhealthy for those who are currently pregnant or trying to get pregnant. Low-carbohydrate diets prior to conception or during the conception period are linked with an increased risk of birth defects and gestational diabetes. And this study found that not even a folate supplement can mitigate the risk.

>> Read More | PCOS and pregnancy: the ultimate guide to conceiving with PCOS

Key takeaways: PCOS and the keto diet

There is little to no evidence to support trying a keto diet for PCOS. A keto diet is likely to be unsustainable and may even contribute to nutrient deficiencies or worsen cholesterol levels. Speak to a doctor or healthcare provider before trying a new way of eating.

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Alex Okell ANutr Founder and Editor

Founder and Editor | Registered Associate Nutritionist


Founder of Be The Collective LTD [The PCOS Collective & The Endo Collective] Alex Okell ANutr is a London-based reproductive health nutritionist with experience in research, private practice and digital media. She holds a Master’s degree in Nutrition from King’s College London and has co-authored papers with the University of Cambridge, King’s College London, The Food Foundation and the Food Standards Agency. Alex offers 1:1 PCOS support in our virtual PCOS clinic.

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