Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy in women, yet there is much debate over the optimal approach to nutrition for its treatment.
PCOS is characterised by hyper-androgenism, oligo/anovulation and polycystic ovaries. The etiology is thought to be closely linked to insulin resistance and hyper-insulinemia, therefore strategies aiming to increase insulin sensitivity are of great importance. Similarly, women with PCOS generally have increased markers of risk for cardiovascular disease (CVD); therefore strategies that improve blood lipid profiles and inflammation are also important.
These strategies include weight loss, low glycemic index/load diets and alterations of the fatty acid composition of the diet.
The evidence presented here suggests current guidelines and practice are at times based on equivocal evidence that could even be detrimental to health; such as a reduction in saturated and an increase in polyunsaturated fats. Interventions should focus on lowering the glycemic index/load of the diet whilst increasing the protein content at the same time as promoting lasting weight loss.
More research should concentrate on lean females as there is a paucity of research in this area and it is one that may help further elucidate the effects of certain dietary composition manipulations, independent of weight loss.
Why can it be difficult for women with PCOS to lose body fat?
  • Often have insulin resistance
  • BMR (Basal metabolic Rate) – the daily amount of calories required each day to keep basic functions alive.
    • can be up to 40% less than those without PCOS
  • Impaired appetite control
  • Metabolic reproductive and psychological impact
  • Higher level of protein oxidation at night time.
Can lifestyle changes and supplementation help?
What does the research say?
  • Nutrition could be a key to increasing insulin sensitivity and thus aiding fat-loss.
  • A calorie deficit is required in every single case, but this will require monitoring/adjusting over time to determine individual BMR levels
    • Work with your coach to get an accurate BMR based on scientific readings and NOT simply guesswork
    • Click here to book an online Skype appointment and we will provide this to you for free.
  • Higher than average protein within diet to retain muscle. 2g x bodyweight in Kg for a target aim for protein in g/per day.
  • Adequate fruit in the diet to reduce protein oxidation
  • Resistance training and/or HIIT training and cardio where possible to improve insulin sensitivity
Supplements for PCOS
  • Omega 3 has been shown to reduce insulin resistance [1]
    • 1.2g per day
  • Vitamin D deficiency is linked to insulin resistance and Type2 Diabetes, also shown to improve menstrual frequency [2]
    • 50,000 IU per week (speak to your doctor to get tested)
  • L-Carnitine – can help with weight-loss and improve insulin sensitivity improvements
    • Dose 250mg day.
  • Pro-Biotics – some emerging research showing weight loss and insulin sensitivity improvement [3]
  • Inositol(in both Myo- and Di- forms) – Shown in research to improve symptoms and fertility. Menstrual cycle dysfunction, hyper-insulinemia hyperandrogenism  [4], [5], [6]
    • Dose 2g day for 6 months
Summary:- Dos and Donts
  • It’s a challenging diagnosis.
  • Prioritise weight-loss, but maybe select preferential times of year, avoiding birthdays, festive periods such as Christmas and Easter.
  • Select 12 weeks of the year where you can dedicate your time to weight loss, rather than ALWAYS being on a diet.

    Even if BMI is normal, aim for lower end of normal
    • Don’t stress on macros (Carbs/Fats etc)
    • Be aware you may need less calories than someone of your age & build without PCOS.
    • Be consistent in your approach and aim for weight-loss over “healthy-eating” in the short term
  • Do resistance training and HIIT to improve insulin sensitivity.
  • Experiment and record. Give yourself a chance to succeed.  Work with a coach to ensure you have someone review your progress from afar.
  • Supplement with Omega-3 and Inositol at the very least.
This content was informed by my nutrition mentor Martin MacDonald and his studies into women with PCOS. You can follow Martin on his social media where he shares a lot of free information on PCOS.
Also, another VERY relevant Doctor in this area is Dr Spencer Nadolsky , who i have worked with and seen present many times.   I share his presentation on PCOS here: –
[1] – Insulin resistance reduced with EPA+DHA – Yang et al (2018) Cross-sectional data on modulation of hormones & lipids • Interventions improve androgenic profiles in PCOS – Phelan et al. (2011) Decreased liver fat in PCOS • Significant compared to placebo. Reduction in systolic & diastolic BP – Cussons et al. (2009) Serum adiponectin levels, insulin resistance & lipid profile • Improved with 1.2g EPA+DHA/day vs placebo – Mohammadi et al. (2012) Differential effects of LC-PUFAs vs. essential n-3 PUFAs • Distinct metabolic and endocrine effects in PCOS -Vargas et al. (2011)
linked to prevalence of T2DM – Pittas et al. (2006) • é fasting glucose & insulin, ê insulin sensitivity – Chiu et al. (2004)
[2] Kotsa et al. (2009) Vitamin D Supplementation & PCOS Improved menstrual frequency –
Jafari-Sfidvajani et al (2018) • 50000IU vitamin D3 per week for 12 weeks or a placebo • These individuals were Vit D insufficient Wehr et al. (2011) • (25(OH)D) levels showed significant negative correlation with IR and positive correlation with insulin sensitivity Selimoglu et al. (2010) • Single dose of 300,000IU vitamin D3 orally • 2 subjects still had levels <20ng/ml • (HOMA)-IR significantly decreased • Decreases in glucose and insulin levels were found but did not reach significance
[3] Samimi et al. (2016)
Inositol Supplementation RCT’s 
[4] – Significant reductions in insulin levels/improvements in insulin sensitivity – Genazzani et al. (2008); Costantino et al. (2009);
[5] -Improved ovarian function, menstrual cyclicality, amenorrhoea & oligomenorrheoa – Genazzani et al. (2008); Gerli et al. (2003); Gerli et al. (2007); Raffone et al. (2010); Pundir et al. meta analysis (2018)
[6] – Significant reductions in free testosterone – Genazzani et al. (2008); Costantino et al. (2009); Pundir et al. meta analysis (2018) Significant weight loss – Gerli et al. (2003); Gerli et al. (2007)
best breakfasts for diabetes
About the Author

James Belbin is the one of the UKs leading nutritionists and habit changes coaches. Specialising in Type 2 Diabetes,  I provide straightforward, personalised no-nonsense guides that help people make significant changes to their nutrition and lifestyle. As an evidence-based nutritionist and habit change coach I can identify the aspects of your diet and lifestyle that are working well for you and build on them. 

I’m a Type 2 Diabetic in remission and lifelong yo-yo dieter so I understand what you’re going through. 

If you’re trying to understand your diabetes diagnosis and how it affects your lifestyle I can help.  

James Belbin - Nutritionist

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