As anyone who has strange stomach issues around their period knows all too well, regular menstruation can throw our internal rhythms way off — and our appetite is no exception. If you find yourself hungry enough to eat multiple lunches for several days in a row, only to end up surfing the crimson wave by the end of the week, it's not in your head, S. Zev Williams, MD, PhD, associate professor of obstetrics and gynecology and chief of reproductive endocrinology and infertility at Columbia University Medical Center, tells Refinery29.
"Women have known for millennia that there seemed to be a link between appetite and the menstrual cycle, [but] recent studies have confirmed this perception," he says.
Throughout the menstrual cycle, hormones such as estrogen and progesterone fluctuate. Citing recent research on this topic, Dr. Williams says that the former tends to decrease appetite, while the latter can cause it to increase, and those shifting levels are timed to coincide with your period. Throughout ovulation, estrogen is on the rise and progesterone remains low. Then, right before the period starts, things flip: Estrogen drops and progesterone spikes, prompting that rumbling in your stomach.
But, our hormones are not working alone. "Metabolic demand also changes through the menstrual cycle," Dr. Williams explains, adding that, in the week before your period starts, your body may demand between 250 and 350 additional calories. Again, for anyone with a period, the idea that shedding your uterine lining and enduring at times debilitating cramps would require a little extra energy comes as no surprise.
As far as period-friendly foods go, Dr. Williams recommends adding more iron to your diet if your flow is on the heavier side. Doing so will help keep your blood counts normal and even help you "avoid anemia, which can cause fatigue," he says.
So, the next time you feel your period approaching, don't be surprised if you're suddenly ravenous for a snack. It's just one of the many, many funny things our bodies do in the name of menstruation.