Our menstrual cycles and periods affect pretty much every area of our lives—how we feel emotionally, how much exercise we want to do, what we want to eat... but did you know they might also have an impact on your metabolism?
To find out how, we spoke to Dr. Virginia J. Vitzthum, director of scientific research at period tracking app, Clue, who explained what we know so far about how periods can affect how quickly we process what we eat.
What have hormones got to do with metabolism?
"Throughout the menstrual cycle, the hormone levels in a person’s body change," says Dr. Vitzthum. "Oestrogen will rise during days 1 to 14 in an average 28-day cycle (known as the follicular phase), dip during ovulation (around day 14), briefly rise again afterwards (the part of the cycle after ovulation is called the luteal phase), falling back to baseline during the final days of the cycle as your period approaches again.
"Progesterone levels also fluctuate—these are very low until the point of ovulation, then rise during the early luteal phase until, like estrogen, they fall in the final days of the cycle," the doctor continues.
These hormonal fluctuations are responsible for a number of changes in your body, and are thought to influence the female metabolism, AKA the bodily processes responsible for turning the food we eat into energy. Keeping up at the back?
So does your metabolism speed up during the menstrual cycle?
Many studies have found that, for some women, energy intake and energy expenditure were greater during the luteal phase (after ovulation) compared to the follicular phase (preceding ovulation). "Taken together, these studies found that energy intake (ie. what you eat) increased by about 100 to 500 calories per day, with energy expenditure (ie. what your body burns) rising by about 100 to 300 calories per day," explains Dr. Vitzthum.
Essentially, what this means is that your metabolism is thought to speed up around the third quarter of your 28-day cycle, but your urge to eat is also greater. "The data suggests that during the later stages of the cycle women consume and burn more calories," summarizes the expert.
Of course, both the menstrual cycle and metabolism are individually affected by many factors like age, diet, and daily activities that vary across individuals. Also, ovulation doesn’t necessarily occur at the same time in every cycle (if it occurs at all). All this means is that getting a definitive, universal answer on how the menstrual cycle affects metabolism will take a long time, with many scientists currently working to unravel these very complex connections.
So, should I change my eating habits throughout my cycle?
Firstly, start by tracking how you're feeling at different times in your cycle using an app (like Clue). If you feel hungrier and more sluggish at certain times of the month, this might just be your body and hormones doing their thing. More data is needed before scientists can use this initial suspected connection to help women on an individual level.
"Biological processes are incredibly complicated, and people differ from each other and over time," explains Dr. Vitzthum. "This is why data collected through personal tracking is valuable to scientists. The connections between different factors can become more obvious lots of women track them."
The more info scientists have, the better the science might serve us in the future. And the more info you have about your personal body, the better you can judge how—if at all—you should adapt eating habits throughout your cycle.
This article originally appeared on Cosmopolitan.com/uk. Minor edits have been made by the Cosmo.ph editors.