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The Menstrual Cycle, Training and Dieting

This one needed some research!

I was intrigued when I came across the idea about how the menstrual cycle might affect a woman’s training and diet, and it some ways it made instinctive sense. There are large variations in our hormones throughout the typical 28 day cycle, and therefore it seems highly likely that this would affect women somehow or other! But it’s important to me to come at it from a scientific perspective (i.e. what’s the evidence?).

First of all, the literature breaks the menstrual cycle down into two main phases: the follicular phase (the first two weeks, starting from day 1 of menstruation) and the luteal phase (the two weeks leading up the menstruation). The follicular phase is characterized by high levels of the hormone oestrogen, with the hormone LH and testosterone peaking at ovulation (typically day 14). Therefore this phase, and especially the time surrounding ovulation, is proposed as being the best time to hit strength goals as the woman can feel more powerful and have a higher pain tolerance. Metabolically, we are more ‘like men’ at this stage in our cycle.

The luteal phase is generally characterized by much higher levels of progesterone (this is for maintaining the uterus lining in preparation for a fertilized egg). Recovery may not be as efficient in this phase; there's a potential higher injury risk. The week before menstruation, PMS could also be a factor, including cravings, lower energy levels and an increased calorie expenditure. It is possible that the woman is burning 90-500 calories more per day (in preparation for a possible pregnancy).

Sounds like we should be taking a rest from the gym at this point right? Not so fast. The body is more than capable of during its usual workload (even if you don’t feel like it!), and there is lots of evidence in female athletes showing that performance is not affected by menstruation. 

The findings may have more of an implication for dieting. Some argue that a calorie deficit is more appropriate during the first two weeks of a woman’s cycle, and a calorie maintenance diet (not surplus!) is more appropriate for the last two weeks of the cycle. This is due to the increased calorie expenditure and therefore cravings which a woman might experience in the two weeks leading up to menstruation, making it difficult to ‘diet’ (but not an excuse to throw healthy eating out the window!!). Therefore, being in a calorie deficit for 2 weeks of the month is better than having a calorie deficit for two weeks and then having a calorie surplus in the final two weeks (leading to potentially no overall deficit and no overall weight loss).

This approach to dieting may suit some women better, but I’d advise against a ‘one size fits all’ approach.With limitations in a lot of studies, I think this is one option, but not the only solution. It all depends on the woman; everyone is different and every cycle is different. It depends on how you experience each part of your cycle. However being more aware of the potential implications it has on your body and decision-making around food, may really help us understand ourselves better and help us achieve our goals better.

How has everyone else experienced this? Does anyone notice any big changes that affect their training and diet? 


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