For several days a month, my appetite knows no bounds – then my period arrives. The relentless hunger is as reliable an indicator that it is approaching as any menstrual tracking app I’ve tried. Despite eating more at this time, I had never considered whether I should be swapping foods in and out, or changing my exercise routine, to support my body on its menstrual journey. That was until I came across the concept of #cyclesyncing on social media – but is there any evidence that we really should change the way we eat and exercise throughout the menstrual cycle?
For the uninitiated, the menstrual cycle has four phases, driven by the rise and fall of hormones such as oestrogen. The first phase is menses, when the lining of the uterus sheds as a period. During the follicular phase, the lining thickens again and an egg-containing follicle within one of the ovaries matures. This is followed by ovulation – the release of that egg – and, finally, the luteal phase, which is the egg’s journey to the uterus, where it may encounter sperm. If pregnancy doesn’t occur, the cycle repeats.
The impact of all this isn’t limited to the reproductive system. Oestrogen receptors, for instance, are found , including in the brain, colon and skin. Levels of this hormone drop towards the end of the luteal phase, which coincides with the usual onset of premenstrual syndrome (PMS). Perhaps it’s unsurprising then that PMS symptoms commonly include headaches, bloating and acne. It’s also normal to lose up to 5 tablespoons of blood during a period, with many women losing more.
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Dietary changes
Such bodily upheavals have helped prompt the appealing idea that lifestyle adjustments throughout the cycle could lessen these effects. For example, clicking on a #cyclesyncing post on Instagram at random, I was advised to switch from carrots to asparagus to cauliflower to quinoa as my cycle progresses. That seems absurdly specific.
Some research supports the idea that women do change their eating habits throughout their cycle. For example, a from 2017 suggests that they consume more calories around ovulation and in the luteal phase – when they also up their carbohydrate, fat and protein intake – than they do during the follicular phase. It’s relatively unclear whether this variation between phases is a good or bad thing. But there is some evidence that foods , fat, sugar and salt may be linked to worse PMS symptoms, while during menses.
You might be tempted, then, to try cutting back on “naughtier” foods during the luteal phase or on caffeine during your period, but there’s no good evidence for this yet – the studies that made these links are based on self-reported questionnaires, a notoriously unreliable way of assessing diet. It’s also unclear whether these foods and caffeine worsen symptoms or if people instead turn to them for comfort.
One randomised controlled suggests that drinking more water during menses really could reduce period pain, but the placebo effect couldn’t be ruled out. However, a recent study found that the placebo effect can reduce period pain even if you know you aren’t taking a real drug or treatment, so it may be worth giving this a go either way.
Varying your exercise
While I would agree with a 2023 that there isn’t enough consistent evidence to support the idea that certain foods can ease menstrual symptoms, what about the suggestion that you should change how you exercise throughout the month? Reproductive hormones do appear to help regulate and the  – an important part of muscle remodelling in response to exercise – so adjusting your workout as they fluctuate may have some logic.
The advice on social media is very inconsistent. But one post recommends running, cycling or high-intensity interval training during the follicular phase and walking or gentle stretches in the luteal one.
There may be something in this. Recent , which hasn’t yet been peer-reviewed, seems to support the idea of the follicular phase being a good time to boost cardiovascular fitness or beat your personal sporting best. żěè¶ĚĘÓƵs at the University of Copenhagen, Denmark, asked 25 female athletes to sprint as fast as they could for 30 seconds while in the luteal or follicular phase. Through a technique called mass spectrometry, the researchers found that the maximum rate of oxygen consumption during exercise (VO2 max) was higher during the follicular phase, suggesting an increased capacity for exercise. They also found that, in the luteal phase, certain pathways in the participants’ mitochondria, which provide cells with energy, were suppressed, impairing their VO2 max.
But this small study stands against a more extensive 2023 of the evidence so far, which concluded that there is no marked difference in exercise performance between these phases and nor is there a change in the growth of muscle cells from resistance training. This is backed up by a recent that found no change in leg muscle mass when women performed weighted leg extensions in either phase.
One reason why it’s hard to get a clear picture is because these kinds of studies often struggle to . Small sample sizes don’t help either, as these studies miss a lot of the that could influence how different phases act on traits like exercise response. We’re already confident that genetics affects the of the menstrual cycle and how periods are, as well as the timing and the . I’m sure my genetic make-up must differ from the 18 women in a recent who experienced no change in appetite from their follicular to luteal phases.
The foggy picture should become clearer with more research. I suspect that, in the future, researchers may establish that it is best to do different exercises during different menstrual phases, but I’m more sceptical about the idea that we should change what we eat to match our reproductive biology. For now, I’ll continue to be as consistently active as I can and to raid my fridge as my period approaches, but maybe I’ll get a few extra glasses of water when it arrives.
