Hello everyone,
A fascinating and debated topic comes to your inbox this week:
What is the best diet for PCOS?
The good news is that there is plenty of research on the best dietary choices for PCOS. The bad news is that the best diet for PCOS is the one you can maintain forever. In this article, I would like to share what has been shown to help with PCOS symptoms, but I would encourage you NOT to pick one dietary pattern and go for it. I truly believe that the best way to change your lifestyle is to understand the why behind these dietary recommendations and implement small changes over a long period.
And please don’t let anyone tell you what diet suits you. You are the one that needs to discover that and whilst that is a harder to do, it’s the only way to health.
The four most researched dietary patterns are:
Low-carbohydrate diet
Mediterranean diet
Ketogenic diet
DASH diet
Low glycemic index/load diet
Please note that most of this research looks at 3-6 months of implementing the diet and usually adds some calorie restriction.
I have synthesised the research on all of these diets and their effect on the most important PCOS marker below:
⬇️ BMI = weight loss
⬇️ Insulin resistance = better glucose metabolism
⬆️ FSH = increased Follicle Stimulating Hormone (this is usually low in women with PCOS)
⬇️ LH = Luteinizing hormone (this is usually high in women with PCOS)
⬇️ Testosterone = reduction in Testosterone levels
⬆️ SHGB = increased Sex Hormone Binding Globulin (the molecules that transport Testosterone - this is usually low in women with PCOS)
⬇️ Cholesterol = usually measured as a decrease in LDL (the bad cholesterol)
⬆️ Menstrual Regularity = bring back your period
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Low-carbohydrate diet
When we discuss a low-carb diet, it doesn’t mean cutting out all carbs and picking a fight with every piece of bread you encounter. Research done with lower carbohydrate diets means carbohydrates accounted for less than 45% of total food intake. This is important because vegetables often are part carbohydrates, and we don’t want to miss out on the nutrients and fibre that these offer.
As you can see in the table above, a lower carbohydrate diet has been shown to help reduce BMI and insulin resistance, lower cholesterol and increase FSH and SHBH. These are great markers to improve when you have PCOS. This diet has not been shown to reduce levels of LH and Testosterone. This means that if a higher level of LH and Testosterone is driving your PCOS, potentially, this won’t be suitable for you.
Mediterranean diet
The Mediterranean diet is my favourite because it’s a diet that has naturally existed for centuries, and it’s probably the closest to eating intuitively. I have found this to be a diet with the fewest studies done specifically on PCOS, but it has a lot of evidence on general health. It is particularly seen as a strong anti-inflammatory diet due to the many antioxidants coming from fruits and vegetables.
A comprehensive guide to this diet can be found here: https://www.healthline.com/nutrition/mediterranean-diet-meal-plan#what-is-it.
Ketogenic diet
This diet aims at keeping carbohydrates below 30-50g/day, with most energy coming from fat sources. I will be honest and say the ketogenic diet is my least favourite. The reason is that our current environment is not designed for it. Since we don’t live on an island where we can fully design our environment, I think this is very hard to adhere to and can lead to food fear and unnecessary restriction. However, a genetic predisposition makes certain people very good at breaking down fat for energy, so I think this can suit some people.
DASH Diet
The DASH diet (Dietary Approaches to Stop Hypertension) was designed for hypertension but can be used by everyone. This diet comprises 52% carbohydrates, 18% proteins, and 30% total fats. The diet limits foods that are high in salt, also called sodium. It also limits added sugar and saturated fat, such as fatty meats and full-fat dairy products. This has been shown to help with menstrual regularly and reduce Testosterone levels.
Low GI (Low Glycemic Index)
In low glycemic diets (LGD), the glycemic index (GI) determines which foods have the least significant effect on blood sugar levels. This diet is particularly effective for PCOS driven by insulin resistance.
A good guide on this diet can be seen here: https://www.healthline.com/nutrition/low-glycemic-diet#other-benefits
So, what is the best diet for PCOS?
As a Nutritionist, I don’t think there is ONE good diet for PCOS. However, I think what all of these diets have in common are the following principles:
Optimising for nutrient-dense foods. I always ask myself: is this food going to nourish me? the less processed and packaged, the higher the chances that it’s higher in nutrients
Filling your day with diverse vegetables and being playful about the ones you chose
Eating 1-2 pieces of fruit per day
Consuming high in fibre foods (I have written a guide on fibre here)
Consuming fish 2-3 times a week or supplementing with Omega 3
Reducing sugars and simple carbohydrate
Increasing protein
Choosing healthy sources of fat
If you think one of the diets above is something you’d like to try, go for it. My only ask is that you are mindful of food rules, disordered eating and being afraid of certain food groups. Eating should be a pleasure, not something we fear.
If you need further support, don’t hesitate to get in touch.
See you next Sunday,
Francesca
1 Sources
References
Aronica, L., Volek, J., Poff, A., & D’agostino, D. P. (2020). Genetic variants for personalised management of very low carbohydrate ketogenic diets. BMJ Nutrition, Prevention & Health, 3(2), 363–373. https://doi.org/10.1136/bmjnph-2020-000167
Asemi, Z., & Esmaillzadeh, A. (2015). DASH diet, insulin resistance, and serum hs-CRP in polycystic ovary syndrome: a randomized controlled clinical trial. Hormone and Metabolic Research, 47(3), 232–238. https://doi.org/10.1055/s-0034-1376990
Barrea, L., Arnone, A., Annunziata, G., Muscogiuri, G., Laudisio, D., Salzano, C., Pugliese, G., Colao, A., & Savastano, S. (2019). Adherence to the Mediterranean diet, dietary patterns and body composition in women with polycystic ovary syndrome (PCOS). Nutrients, 11(10), 2278. https://doi.org/10.3390/nu11102278
Paoli, A., Mancin, L., Giacona, M. C., Bianco, A., & Caprio, M. (2020). Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. Journal of Translational Medicine, 18(1). https://doi.org/10.1186/s12967-020-02277-0
Saadati, N., Haidari, F., Barati, M., Nikbakht, R., Mirmomeni, G., & Rahim, F. (2021). The effect of low glycemic index diet on the reproductive and clinical profile in women with polycystic ovarian syndrome: A systematic review and meta-analysis. Heliyon, 7(11), e08338. https://doi.org/10.1016/j.heliyon.2021.e08338
Shang, Y., Zhou, H., He, R., & Lu, W. (2021). Dietary modification for reproductive health in women with polycystic ovary syndrome: A systematic review and meta-analysis. Frontiers in Endocrinology, 12. https://doi.org/10.3389/fendo.2021.735954
Zhang, X., Zheng, Y., Guo, Y., & Lai, Z. (2019). The effect of low carbohydrate diet on polycystic ovary syndrome: A meta-analysis of randomized controlled trials. International Journal of Endocrinology, 2019, 1–14. https://doi.org/10.1155/2019/4386401
Disclaimer: We are all unique in our ways, so this information is for educational purposes only. In my communications, I summarise research data and bring my experience. This shouldn’t be viewed as medical advice at any point. Please further consult your healthcare provider about your health needs.