The effects of ketogenic diet on polycystic ovary syndrome: A systematic review and meta-analysis

Abstract

Background and aim: Polycystic ovary syndrome (PCOS) is a common endocrine disorder linked to obesity, insulin resistance, and reproductive dysfunction. While dietary modification is central to management, the optimal approach remains unclear. This systematic review and meta-analysis evaluated the effects of the ketogenic diet on anthropometric, metabolic, and endocrinological outcomes in women with PCOS.

Methods: A systematic search of five databases (inception-February 2025) identified studies reporting outcomes in women with PCOS following a ketogenic diet. Meta-analyses compared pre- and post-ketogenic diet outcomes (primary analysis) and ketogenic diet versus other diets (secondary analysis). Summary mean differences (MDs) with 95 % confidence intervals (CIs) were calculated using a random-effects model. Risk of bias and evidence quality were assessed using validated tools and the GRADE approach.

Results: Fifteen studies were included in the review, of which ten met the criteria for inclusion in the meta-analysis. Most participants in the included studies had a BMI exceeding 25 kg/m². In the primary analysis, ketogenic diet led to significant reductions in BMI (MD: -3.38 kg/m², 95 % CI: 2.53 to 4.23, I² = 0 %), weight (MD: -10.77 kg, 95 % CI: 8.73 to 12.81, I² = 0 %), and waist circumference (MD: -8.93 cm, 95 % CI: 5.66 to 12.19; I² = 44 %). Reductions were also observed in luteinising hormone (LH) levels (MD: 4.07, 95 % CI: 3.36 to 4.79, I² = 0 %), menstrual cycle duration (MD: 26.06, 95 % CI: 2.28 to 49.85, I² = 68 %), and insulin resistance (MD: 2.43; 95 % CI: 1.16 to 3.69, I² = 95 %). In the secondary analysis, ketogenic diet showed superior effects on BMI (MD: -1.65, 95 % CI: -2.76 to -0.55, I² = 0 %) and weight loss (MD: -4.98, 95 % CI: -9.05 to -0.91, I² = 7 %) as well as LH levels (MD 1.68, 95 % CI: -3.18 to -0.19, I² = 30 %) and insulin resistance (MD: -1.71, 95 % CI: -2.98 to -0.43, I² = 90 %) compared to other diets, though results for androgen and lipid parameters were inconsistent. Heterogeneity was high for most of the studied outcomes.

Conclusion: The ketogenic diet appears to be a promising dietary intervention for improving weight, insulin sensitivity, and reproductive hormone profiles in women with PCOS and a BMI exceeding 25 kg/m². Nonetheless, the considerable heterogeneity among included studies and variations in study quality warrant cautious interpretation of these findings. Further high-quality, long-term randomized controlled trials are needed to more definitively establish the efficacy and safety of the ketogenic diet in women with PCOS.

Keywords: Carbs; Diet; Keto; PCOS; Polycystic ovary syndrome.