Is a Ketogenic Diet Best for PCOS?

Untitled keto diet

The Western diet, which is made up of high carbohydrates, low fiber and fat has consequently led to the increase in obesity, diabetes, as well as mental health disorders such as depression and anxiety.


Low carbohydrate/ High-fat diets were frowned upon for many years due to the supposed detrimental health effects a high-fat diet can cause. Although there have been many studies demonstrating the benefits of lowering dietary carbohydrates for our cardiovascular health and metabolism.


There are many diets claiming to be the best for our overall health, but is there a specific diet that is best for Polycystic Ovarian Syndrome (PCOS).


It is likely that you have heard about the Ketogenic Diet, however, you may not be sure what the benefits are and if this diet is suitable for you.


What is the Ketogenic Diet?


The Ketogenic Diet was developed in the 1920's as a treatment for epilepsy, however, a ketogenic diet can be dated back to our ancestors. A ketogenic diet was the type of lifestyle in which our ancestors lived for tens of thousands of years. A diet high in fat and low in glucose was what kept them going.


Since the development of the Ketogenic Diet, research has shown how a ketogenic diet can treat many other chronic illnesses.


Ketogenic diets consist of high fat, moderate protein and low carbohydrates. However, there are types of ketogenic diets in which you eliminate carbs completely. High carbohydrate foods, such as bread, pasta, starchy fruits and vegetables, sugar and grains are eliminated. While high-fat foods are increased, such as coconut oil, avocado, butter and cream.


It is often a 4:1 weight-based ratio of fat to combined protein and carb. The macronutrient ratios of ketogenic diet vary within these ranges, 60-75% of calories from fat (or even more), 15-30% of calories from protein, and 5-10% of calories from carbs.

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What is Ketosis


Ketosis is a metabolic process. Our bodies turn into a state of ketosis, after 3-4 days, due to a low carbohydrate consumption. As a result of the low carbs our blood sugar levels begin to drop and in order to survive, our bodies turn to fat stores for energy. The bodies stored or consumed fats are broken down into fatty acids in the liver and this process is called beta - oxidation. As a result of the breakdown, a byproduct called Ketones is built up in the blood, which is then lost through urine.


Ketones are an acid, the development of ketones indicates that fat breakdown is working, in small amounts is nothing to worry about. However, high levels of ketones can be poisonous and can result in a process called ketoacidosis.


Don't our bodies need carbohydrates?


Our body needs glucose, not carbohydrates.

Glucose is a major fuel source for our muscles, about three - fourths of glycogen in the body is stored in the muscles. Our brain also prefers glucose as the main fuel source, consuming about 120g daily. However, research indicates that the brain and body prefer using ketones, and run 70% more efficiently than when using glucose.


The body has a mechanism in which it can use when glucose levels are low. The brain tells the liver to produce ketone like compound called beta-hydroxybutyrate. This compound, therefore allows the brain to function efficiently without glucose.


Benefits of the Ketogenic Diet


Improved Fertility and Ovulation


The American College of Obstetricians and Gynecologists identified that the women undertaking In Vitro Fertilization (IVF) treatment who consumed high levels of protein and low levels of carbs had better quality eggs and embryos.

Further research conducted at the Delaware Institute of Reproductive Medicine found patients whose daily protein intake was 25% or more of their diet and whose carbohydrate intake was 40% or less of their diet had four times the pregnancy rates of patients who ate less protein and more carbs daily before and during IVF cycle.


The Nurse's Health Study (NHS II) found that a high carbohydrate diet is linked to ovulatory infertility. Results show women who consumed high levels of carbs had a 78% greater risk of ovulatory infertility. While animal protein consumption was associated with a 20% higher risk of ovulatory infertility. Moreover, the study showed vegetable protein consumption was associated with a 43% lower risk.


Although, research does suggest that a ketogenic diet should not be followed during pregnancy as it may affect embryonic development.


Increases Insulin Sensitivity

Following a Ketogenic Diet can improve insulin sensitivity as a result of the body utilising it's fat stores for energy. Due to the low carbohydrate intake, there is no glycogen and therefore both blood sugar and insulin will go down.

A study conducted by Mavropolous et al (2005) found women with PCOS had improved insulin levels when following a low - carb ketogenic diet. Insulin levels reduced from 23.5 μIU/ml to 8.2 μIU/ml (p = 0.002). Reducing hyperinsulinemia, which is associated with PCOS, can also help reduce androgen secretion from the ovary and increase circulating sex hormone binding globulin.


A low carb ketogenic diet (LCKD) has shown to be the most effective in improving glycemic control. Westman et al research results show 95.2% LCKD participants eliminated or reduced their medication, compared with 62.1% Low Glycemic participants.


Weight loss


Research has supported the benefit a ketogenic diet has on weight loss. Dashti et al found in their study that weight and body mass index of patients decreased significantly (P<0.0001).


Furthermore, Brehm et al a study concluded that a low carbohydrate ketogenic diet is more effective than a low calorie or fat diet, with individuals on an LCKD losing 2.2 more of their weight.


A 12-month study found, on average, participants in the low-carbohydrate group lost 5.3 kg and those in the low-fat group lost 1.5 kg.

In addition, studies show a ketogenic diet can reduce your appetite, due to the high calories that are in fat and the high protein intake, this may also be a reason for the weight loss.


Increases HDL levels


A ketogenic diet can significantly increase HDL "good cholesterol". A study in the British Journal of Nutrition by Bueno et al found participants in the LCKD (50 grams of carbohydrates) significantly improved their HDL by of 0.12 mmol/L compared to 0.06 mmol/L in the Low Fat Diet group (LFD).


Decrease LDL levels


Along with improving HDL levels, studies have shown how it can also lower LDL "bad cholesterol". Research found LDL particle concentration decreased by 11% when following a ketogenic diet.


While both a LCKD and low-fat diet helps with weight loss, research has shown how a LCKD is beneficial for overall cardiovascular health. A high carbohydrate consumption leads to decreased insulin sensitivity,  insulin resistance and inflammation. Whereas a low carbohydrate diet can help increase insulin sensitivity, in turn improving adipocyte function. When adiponectin levels increase weight loss also increases.


Bottom Line


Should you follow a Ketogenic Diet?


This post is not to say you should follow a ketogenic diet, I believe that there is no single or specific diet for PCOS. Since all our bodies are different and there is not one type of PCOS, what works for one person may not work for another. However, many studies have identified a vast array of health benefits for following a Low Carbohydrate Ketogenic Diet.


Most noteworthy is that it is a high carbohydrate diet can have negative effects on your health. Therefore, you do not have to follow a low carb ketogenic diet, reducing your carbohydrate and sugar intake, through eating whole foods and less processed and packaged foods may allow you to see progress, without limiting your carbs to less than 100g or eliminating them. It is all about finding what works for you and your body.


Furthermore, if you decide to go on a Ketogenic Diet you should visit a doctor or health professional who can help guide you on how to begin.



McIntosh, J. (2015). Ketosis: What Is Ketosis? Medical News Today. Available from:  . [Accessed 20 February 2017].

(2013). High Protein, Low Carb Diets Greatly Improve Fertility. The American Congress of Obstetricians and Gynecologists. Available from: . [Accessed 20 February 2017].

Kulaka, D., Polotsky, A.J. (2012). Should the ketogenic diet be considered for enhancing fertility? Available from: [Accessed 20 February 2017].


Sussman, D.,  Eede, M., Wong, MD., Adamson, SL.,  Henkelman, M. (2013). Effects of a ketogenic diet during pregnancy on embryonic growth in the mouse. BMC Pregnancy Childbirth. 13: 109. Available from: .  [Accessed 20 February 2017].


Mavropoulos, JC., Yancy, WS., Hepburn, J., Westman, EC. (2005). The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: A pilot study. Nutrition and Metabolism. 2. Available from: .  [Accessed 20 February 2017].


Brehm BJ, Seeley RJ, Daniels SR, D'Alessio DA. (2003). A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. The Journal of Clinical Endocrinology & Metabolism. 88(4):1617-23. Available from: [Accessed 22 February 2017].

Westman, EC., Yancy, Jr, WS., Mavropoulos, JC., Marquart, M., McDuffie, JR. (2008).The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutrition and Metabolism. 5. Available from: [Accessed 22 February 2017].


Dashti, HM., Mathew, TC., Hussein,T., Asfar, SK. Behbahani, A., Khoursheed,MK., Al-Sayer, HM,

Bo-Abbas, YY.and Al-Zaid, SN.(2004). Long-term effects of a ketogenic diet in obese patients. Experimental and Clinical Cardiology. 9(3): 200–205. Available from: . [Accessed 22 February 2017].


Stephens JM (2012) The Fat Controller: Adipocyte Development. PLoS Biol 10(11): e1001436. doi:10.1371/journal.pbio.1001436

L. Schwingshackl and G. Hoffmann. (2013). Low-carbohydrate diets impair flow-mediated dilatation: evidence from a systematic review and meta-analysis. British Journal of Nutrition.110, 969–970. Available from: [ Accessed 22 February 2017].

Paoli, A. (2014).Ketogenic Diet for Obesity: Friend or Foe? International Journal of Environmental Research and Public Health. 11(2): 2092–2107. Available from: [ Accessed 22 February 2017].

Hauner H, Bechthold A, Boeing H, Brönstrup A, Buyken A, Leschik-Bonnet E, Linseisen J, Schulze M, Strohm D, Wolfram G. (2012). Evidence-based guideline of the German Nutrition Society: carbohydrate intake and prevention of nutrition-related diseases. Annals of Nutrition and Metabolism. Available from: [ Accessed 23 February 2017].









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