Best PCOS Diet

Updated: 21-August-2024

There is literally an infinite number of diets to choose from, and a new one popping up every month, so which one is the right one for women with PCOS in 2024?

Let’s have a look at the evidence.

To date, several diets have been trialled in women with PCOS. These include:

⦁ Low carb diet
⦁ Low fat diet
⦁ Mediterranean diet
⦁ Ketogenic diet
⦁ Low inflammatory diet

Low carb diet

As explained by Barrea et al., high carbohydrate intake and low-grade inflammation cooperate with insulin resistance and hyperandrogenism to exacerbate the severity of PCOS.¹ With 65-80% of women with PCOS being resistant to insulin, this makes a low carb diet (< 26% carbohydrates) particularly important.²

A meta-analysis of low carb diet studies involving women with PCOS reported significantly reduced BMI, androgen and insulin resistance levels along with improved lipid (fat) metabolism after just 2 months without necessarily reducing calorie intake.³

Low fat diet

Contrary to recent high fat diets success across many studies, high fat diets are not particularly suitable for women with PCOS. This is because some (saturated) fats increase inflammation and insulin resistance much more in women with PCOS, than non-PCOS women, irrespective of BMI or adiposity, which leads to increased androgen production by the ovaries.⁴

In the study which reported the greatest benefit of a low fat diet in women with PCOS, saturated fat intake was restricted to just 6 grams per day, with no more 30 grams per day in total fats.⁵ This helped women achieve a similar reduction of fat mass in less time (6 vs. 12 weeks) and improve metabolic outcomes significantly more than a traditional ketogenic diet.⁶

In a small comparative study, the low fat diet also proved to be more effective (but not statistically significant) than the low-glycaemic load diet among obese girls with PCOS.⁷

Mediterranean diet

The Mediterranean diet is an anti-inflammatory diet, rich in complex carbohydrates and fiber, and high in monounsaturated fats which is good for PCOS.

A link between adherence to the Mediterranean diet and the clinical severity of PCOS was first reported in 2019 during an observational study.⁸ In 2022, a larger and more comprehensive study confirmed the original finding suggesting that the Mediterranean diet plays a protective role in women with PCOS.⁹

In the 2022 study by Mei et al., 59 obese women with PCOS were randomly allocated one of two energy-restricted diets (<1400Kcal/day), the Mediterranean low carb diet or the low fat diet, for a period of 12 weeks. At the end of the trial, women who underwent the Mediterranean low carb diet had a more significant improvement in weight and body measurements, sex hormones and metabolic parameters (Table 1).

	Mediterranean low carb	Low fat
Weight (kg)	−6.1	−4.8
BMI (kg/m2)	−2.1	−1.8
Bodyfat (%)	−3.0	−1.2
Total testosterone (ng/mL)	−0.20	+0.08
LH (mIU/mL)	−5.3	−3.4
LH/FSH	−1.2	−0.7
Fasting plasma glucose (mmol/mL)	−0.50	+0.05
Fasting insulin (μU/ml)	−8.5	−4.9
HOMA-IR	−2.2	−1.1
QUIKI	+0.028	+0.014
Triglyceride (mmol)	−0.8	−0.3
Total cholesterol (mmol)	−1.5	−0.4
LDL cholesterol (mmol)	−0.7	−0.4

In addition to these improvements, more than 70% of participants restored their normal menstrual cycle (irrespective of diet) by the end of the trial.

Ketogenic diet

The ketogenic diet is a very low carb, high fat diet that activates ketosis, a metabolic state which utilises fat and ketones for energy.

Unfortunately, some types of fat (saturated) are especially unhealthy for women with PCOS. González et al. reported that women with PCOS display a proinflammatory response to saturated fat consumption irrespective of BMI compared to non-PCOS women.⁴

This explains the inconsistent results of 2 studies which featured women with PCOS undertaking different ketogenic diets. The modified ketogenic diet lower in saturated fat (1.5% vs. 39%) achieved a similar reduction of fat mass in less time (6 vs. 12 weeks) and improved metabolic outcomes significantly more than the traditional ketogenic diet.^5,6 Note, both diets consisted of 1.1-1.2 grams of protein per kilo of body weight.

This explains to some degree why the latest ketogenic diets are now both low in carbohydrates and fats.¹⁰

Low inflammatory diet

A low inflammatory diet is based on the dietary inflammatory index (DII) which scores 45 different food parameters according to their pro or anti- inflammatory effect.¹¹ In two completely independent studies, both research teams concluded that a high DII increased the risk of PCOS, suggesting a low inflammatory diet is beneficial in women with PCOS.^12,13 This is not overly surprising given PCOS is an inflammatory condition.

Upon reviewing the dietary inflammatory index, we notice a familiar pattern. Saturated fats, trans-unsaturated fats, total fats, energy, cholesterol, carbohydrates and vitamin B12 (found in animal foods) are all pro-inflammatory, in order of highest to lowest. In short, a low inflammatory diet resembles a low carb and fat type of Mediterranean diet.

A Final Tip From Fertility Science

Without overly complicating diet plans, here are 5 things you can also do to really boost the impact of your diet on PCOS according to science:

1. Control calorie intake
2. Select low GI foods
3. Increase protein intake
4. Restrict eating to an 8-hour period
5. Eat less but more often
6. Supplement your diet with vitamins and minerals

As obvious as it sounds, controlling calorie intake is especially important for women with PCOS as simply overeating has an inflammatory effect on the body. Either way, women trying to lose weight sometimes see better results with very low calorie diets (<800 day) than moderately energy deficient diets.^14,15

Secondly, low GI foods such as pulses (i.e. split-peas, dry beans, lentils, and chickpeas) is one of mother nature’s superfood for PCOS. These seeds are high in fiber, low in fat and contain complex carbohydrates with a low GI. Women with PCOS who modified their diet to include 2 pulse-based meals per day, without any change in calories, significantly improved their metabolic profile after just 4 months (Table 2).¹⁶

	Pulse-Based Diet	Therapeutic Lifestyle Changes Diet
Total insulin AUC (µIU/mL × min)	−121	−27
Diastolic blood pressure (mmHg)	−3.6	−0.2
Triglyceride (mmol/L)	−0.2	0.0
LDL cholesterol (mmol/L)	−0.2	0.0
HDL cholesterol (mmol/L)	+0.1	−0.1
Total cholesterol/HDL cholesterol	−0.4	+0.1

Low protein intake is associated with inflammation (IL-6, TNF-α), oxidative stress (MDA) and obesity.^17,18 Experts suggest a long-term diet high in protein (>30%) amplifies the loss of weight and body fat.¹⁹ This is probably because high protein diets significantly decrease insulin levels in women with PCOS and improve insulin resistance.²⁰ In fact, having 35g of whey protein isolate 30 mins before carbohydrate intake (75g oral glucose tolerance test), significantly improves insulin response, lowers glucose levels, and decreases total cholesterol in women with and without PCOS.²¹

Restricting eating to an 8-hour period each day (i.e. intermittent fasting) is also helpful for women with PCOS. In the 2 studies to date, intermittent fasting (between 4-6pm to 8am) causes significant weight loss, increases insulin sensitivity, reduces hyperandrogenism (TT, SHBG), hirsutism and inflammation (hsCRP), while liver health (ALT) and menstrual cycles significantly improve.^22,23

Experts also recommend limiting alcohol intake or skipping of meals to help maintain regular cycles.^24,25,26 Similarly, eating a large dinner instead of a large breakfast worsens insulin resistance and hyperandrogenism in women with PCOS.²⁷ Predictably, research shows that having 6+ smaller meals a day instead of the usual 3 significantly improves insulin sensitivity.^28,29 This meal plan may have additional benefits, namely reducing testosterone levels throughout the day.³⁰

Finally, women with PCOS are often deficient in several vitamins and minerals which disrupt various systems in the body and aggravates PCOS.

Fortunately, addressing any (remaining) deficiencies with supplements after dietary changes usually corrects this and reduces the severity of PCOS further.

References

1. Barrea L, et al. (2018). Source and amount of carbohydrate in the diet and inflammation in women with polycystic ovary syndrome. https://doi.org/10.1017/s0954422418000136 ↩︎
2. Oh R, et al. (2022). Low Carbohydrate Diet. https://pubmed.ncbi.nlm.nih.gov/30725769/ ↩︎
3. Zhang X, et al. (2019). The Effect of Low Carbohydrate Diet on Polycystic Ovary Syndrome: A Meta-Analysis of Randomized Controlled Trials. https://doi.org/10.1155/2019/4386401 ↩︎
4. Gonzalez F, et al. (2020). Inflammation Triggered by Saturated Fat Ingestion Is Linked to Insulin Resistance and Hyperandrogenism in Polycystic Ovary Syndrome. https://doi.org/10.1210/clinem/dgaa108 ↩︎
5. Cincione R I, et al. (2021). Effects of Mixed of a Ketogenic Diet in Overweight and Obese Women with Polycystic Ovary Syndrome. https://doi.org/10.3390/ijerph182312490 ↩︎
6. Paoli A, et al. (2020). Effects of a ketogenic diet in overweight women with polycystic ovary syndrome. https://doi.org/10.1186/s12967-020-02277-0 ↩︎
7. Wong J, et al. (2016). A randomized pilot study of dietary treatments for polycystic ovary syndrome in adolescents. https://doi.org/10.1111/ijpo.12047 ↩︎
8. Barrea L, et al. (2019). Adherence to the Mediterranean Diet, Dietary Patterns and Body Composition in Women with Polycystic Ovary Syndrome (PCOS). https://doi.org/10.3390/nu11102278 ↩︎
9. Mei S, et al. (2022). Mediterranean Diet Combined With a Low-Carbohydrate Dietary Pattern in the Treatment of Overweight Polycystic Ovary Syndrome Patients. https://doi.org/10.3389/fnut.2022.876620 ↩︎
10. Pandurevic S, et al. (2023). Efficacy of very low-calorie ketogenic diet with the Pronokal® method in obese women with polycystic ovary syndrome: a 16-week randomized controlled trial. https://doi.org/10.1530/ec-22-0536 ↩︎
11. Shivappa N, et al. (2014). Designing and developing a literature-derived, population-based dietary inflammatory index. https://doi.org/10.1017/s1368980013002115 ↩︎
12. Wang Q, et al. (2022). Higher dietary inflammation potential and certain dietary patterns are associated with polycystic ovary syndrome risk in China: A case-control study. https://doi.org/10.1016/j.nutres.2021.12.006 ↩︎
13. Sharkesh E, et al. (2021). The dietary inflammatory index is directly associated with polycystic ovary syndrome: A case-control study. https://doi.org/10.1111/cen.14672 ↩︎
14. Deshmukh H, et al. (2023). The Effect of a Very-Low-Calorie Diet (VLCD) vs. a Moderate Energy Deficit Diet in Obese Women with Polycystic Ovary Syndrome (PCOS)—A Randomised Controlled Trial. https://doi.org/10.3390/nu15183872 ↩︎
15. Nikokavoura E A, et al. (2015). Weight loss for women with and without polycystic ovary syndrome following a very low-calorie diet in a community-based setting with trained facilitators for 12 weeks. https://doi.org/10.2147/dmso.s85134 ↩︎
16. Kazemi M, et al. (2018). A Comparison of a Pulse-Based Diet and the Therapeutic Lifestyle Changes Diet in Combination with Exercise and Health Counselling on the Cardio-Metabolic Risk Profile in Women with Polycystic Ovary Syndrome: A Randomized Controlled Trial. https://doi.org/10.3390/nu10101387 ↩︎
17. Mizgier M, et al. (2021). Relation between Inflammation, Oxidative Stress, and Macronutrient Intakes in Normal and Excessive Body Weight Adolescent Girls with Clinical Features of Polycystic Ovary Syndrome. https://doi.org/10.3390/nu13030896 ↩︎
18. Mizgier M, et al. (2020). Risk Factors of Overweight and Obesity Related to Diet and Disordered Eating Attitudes in Adolescent Girls with Clinical Features of Polycystic Ovary Syndrome. https://doi.org/10.3390/jcm9093041 ↩︎
19. Toscani M K, et al. (2011). Effect of high-protein or normal-protein diet on weight loss, body composition, hormone, and metabolic profile in southern Brazilian women with polycystic ovary syndrome: a randomized study. https://doi.org/10.3109/09513590.2011.564686 ↩︎
20. Wang F, et al. (2024). Effects of high-protein diets on the cardiometabolic factors and reproductive hormones of women with polycystic ovary syndrome: a systematic review and meta-analysis. https://doi.org/10.1038/s41387-024-00263-9 ↩︎
21. Zumbro E L, et al. (2021). Whey Protein Supplementation Improves the Glycemic Response and May Reduce Non-Alcoholic Fatty Liver Disease Related Biomarkers in Women with Polycystic Ovary Syndrome (PCOS). https://doi.org/10.3390/nu13072451 ↩︎
22. Li C, et al. (2021). Eight-hour time-restricted feeding improves endocrine and metabolic profiles in women with anovulatory polycystic ovary syndrome. https://doi.org/10.1186/s12967-021-02817-2 ↩︎
23. Talebi S, et al. (2024). The effects of time-restricted eating alone or in combination with probiotic supplementation in comparison with a calorie-restricted diet on endocrine and metabolic profiles in women with polycystic ovary syndrome: A randomized clinical trial. https://dom-pubs.pericles-prod.literatumonline.com/doi/10.1111/dom.15801 ↩︎
24. Łagowska K and Pieczyńska J M, (2022). Not only diet quality and physical activity but also snacking and skipping meals could be related with menstrual disorders in PCOS. https://doi.org/10.1080/03630242.2022.2106529 ↩︎
25. Oyelowo O, et al. (2022). Skipping the first active meal appears to adversely alter reproductive function in female than male rats. https://doi.org/10.1016/j.crphys.2022.10.001 ↩︎
26. Fujiwara T, et al. (2009). Skipping breakfast adversely affects menstrual disorders in young college students. https://doi.org/10.1080/09637480802260998 ↩︎
27. Jakubowicz D, et al. (2013). Effects of caloric intake timing on insulin resistance and hyperandrogenism in lean women with polycystic ovary syndrome. https://doi.org/10.1042/CS20130071 ↩︎
28. Papakonstantinou E, et al. (2016). Effect of meal frequency on glucose and insulin levels in women with polycystic ovary syndrome: a randomised trial. https://doi.org/10.1038/ejcn.2015.225 ↩︎
29. Bozbulut R, et al. (2023). Beneficial effects of RESMENA diet on anthropometric, metabolic and reproductive profile in adolescents with obesity and polycystic ovary syndrome: a randomized controlled intervention study. https://doi.org/10.1159/000535053 ↩︎
30. Katcher H I, et al. (2008). Comparison of hormonal and metabolic markers after a high-fat, Western meal versus a low-fat, high-fiber meal in women with polycystic ovary syndrome. https://doi.org/10.1016/j.fertnstert.2008.01.035 ↩︎