PMS on Keto: Better, Worse or Different
The ketogenic diet alters how the body processes energy, which may influence premenstrual syndrome (PMS) symptoms. By shifting from glucose to fat metabolism, keto affects hormones like oestrogen and progesterone that fluctuate during the menstrual cycle. For some women, this leads to fewer mood swings and less bloating. Others report temporary symptom changes during the keto adaptation phase.
How keto interacts with menstrual hormones
Carbohydrate restriction lowers insulin levels, which in turn may reduce excess oestrogen production. A 2005 pilot study found that women with polycystic ovary syndrome (PCOS) — a condition linked to hormonal imbalance — saw improvements in menstrual regularity on keto (Mavropoulos et al., 2005). While not all PMS stems from PCOS, the mechanism suggests keto could moderate extreme hormonal swings. Progesterone levels, which typically drop before menstruation causing irritability, may stabilise with consistent fat intake.
Cravings and energy fluctuations
PMS often brings intense cravings for sugar and refined carbs. The ketogenic diet’s high-fat approach provides slow-burning energy that may curb these urges. At Sainsbury’s, a 200g bar of 90% dark chocolate costs £2 and fits keto macros better than milk chocolate. However, some women find their usual PMS cravings shift toward salty foods like olives or cheese due to keto electrolyte needs. Energy levels on keto tend to be more stable, potentially reducing the fatigue many experience premenstrually.
What this means in practice
Track symptoms for three cycles to identify patterns. In winter months when vitamin D is low, consider adding oily fish like £3.50 tinned sardines from Aldi to support mood. The NHS recommends 400 IU of vitamin D daily from October to March. Some women report lighter periods on keto, possibly due to reduced inflammation. Others notice temporary changes in cycle length during the first few months of carbohydrate restriction.
Frequently asked questions
Does keto stop PMS completely?
No diet eliminates PMS entirely, as it’s a complex interaction of hormones. However, some women report milder symptoms like less breast tenderness or fewer mood swings after adapting to keto.
Why do some feel worse initially?
The first few cycles on keto may differ as the body adjusts to fat metabolism. Electrolyte imbalances can mimic PMS fatigue or headaches, so ensure adequate sodium, potassium and magnesium.
Can keto help with menstrual migraines?
Reduced blood sugar swings on keto may decrease migraine frequency for some. A 2017 review noted keto’s potential neurological effects (Kosinski & Jornayvaz, 2017), though more research is needed specifically on menstrual migraines.
The bottom line
The ketogenic diet changes how the body fuels itself, which may alter PMS symptoms for better or worse during the adaptation period. Most evidence suggests long-term benefits for hormonal balance, particularly for women with insulin resistance. Tracking your cycle alongside food intake provides the clearest personal picture. If you’d rather not do the macro maths yourself, the Keto Dieting app does it for you on Google Play and the App Store.
References
- Mavropoulos JC, Yancy WS, Hepburn J, Westman EC (2005). The effects of a low-carbohydrate, ketogenic diet on the polycystic ovary syndrome: a pilot study. Nutrition & Metabolism. https://doi.org/10.1186/1743-7075-2-35
- Kosinski C, Jornayvaz FR (2017). Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies. Nutrients. https://doi.org/10.3390/nu9050517
