Do I Need to Go Carb-Free for PCOS?
If you’ve been diagnosed with PCOS you may have seen advice to go carb-free or low-carb or try diets like Keto and Atkins. But why is this dietary advice so commonly seen for people with PCOS and is there any truth behind it?
PCOS Basics
PCOS is a chronic endocrine disorder that affects 1 in 10 women in the UK (1). There are a variety of symptoms associated with PCOS including acne, oily skin, rapid weight gain, irregular periods, difficulty getting pregnant, excess hair growth and hair loss on the head (2).
One of the mechanisms associated with PCOS is insulin resistance which is when the insulin system that allows glucose to pass into the cells is not working optimally. This in turn triggers the ovaries to increase testosterone production, exacerbating symptoms of PCOS.
Cutting Out Carbs with PCOS
In regards to cutting or reducing carbohydrate content, the thinking behind this is that the fewer carbohydrates we consume, the less insulin will be produced as we don’t need as much to move glucose into the cells. But does the evidence back this up?
A low-carbohydrate diet can be defined as eating less than 130g of carbohydrates per day and a ketogenic diet can be defined as a high-fat, adequate-protein, low-carbohydrate diet with less than 50g of carbohydrates per day.
What Does the Evidence Say?
A 2005 pilot study investigated the impact of a low-carbohydrate, ketogenic diet on eleven women in North Carolina. Despite this study claiming that all subjects lost weight and improved free testosterone levels, LH/FSH ratio, and fasting insulin, only five subjects actually managed to complete the six-month study (3), likely because of the restrictive nature of the low-carbohydrate, ketogenic diet.
Similarly, a 2020 study looked at the effects of a ketogenic Mediterranean diet on twenty-four women with PCOS but after the twelve-week intervention period, only fourteen completed the study. This study found this way of eating improved anthropometric, biochemical and hormonal variables across all participants (4).
Despite the seemingly promising evidence these studies suggest, the fact that the participant numbers are so small and that the intervention period is short, paired with a high drop-out rate, we can’t conclude whether low-carbohydrate diets are beneficial for people with PCOS. When we see a high drop out rate in a dietary study, like we do with these mentioned above, it is usually because the diet is not easy to follow and the participants are fed up with it!
So Should We Cut Carbs If We Have PCOS?
Eating a low-carbohydrate diet, considering that our brains preferred energy source is glucose, can be extremely difficult, impacting social situations and may even lead to symptoms like mental fog, fatigue and headaches. Plus, going low-carbohydrate may leave you at risk of deficiencies including below-optimal fibre, iron, folate, niacin and zinc intake (5).
So instead of going carbohydrate-free, what can we do to manage PCOS symptoms?
Take a look at this blog post for more diet-free PCOS tips.
References
BDA, 2016. Polycystic Ovary Syndrome – the fundamentals[online]. Available from: https://www.bda.uk.com/resource/polycystic-ovary-syndrome-the-fundamentals.html
NHS, 2019. Symptoms Polycystic ovary syndrome[online]. Available from: https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/symptoms/
Mavropoulos JC, Yancy WS, Hepburn J, Westman EC. The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. Nutr Metab (Lond). 2005;2:35. Published 2005 Dec 16. doi:10.1186/1743-7075-2-35
Paoli A, Mancin L, Giacona MC, Bianco A, Caprio M. Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. J Transl Med. 2020;18(1):104. Published 2020 Feb 27. doi:10.1186/s12967-020-02277-0
BDA, 2016. Food Fact Sheet: Carbohydrates [online]. Available from: https://www.bfwh.nhs.uk/wp-content/uploads/2016/04/BDA-Carbs.pdf
