In the immortal words of Cady Heron, "This is all water weight"—or at least it might be. Here, the potential (totally normal) causes of period weight gain.


You've been exercising and eating healthy, but the scale just threw you a curveball, clocking in at a few more pounds than last week. Or maybe your jeans just feel tighter. Or your body doesn't quite feel like its usual self.

Don't worry—if your surprise weigh-in lands the week before your period, you can chalk it up to water weight, reassures Raquel Dardik, M.D., a gynecologist at NYU Langone Medical Center. "Weight gain happens five days before your period, but you'll be back to normal once you start," she explains. (Related: Your Menstrual Cycle Phases—Explained)

Reasons for Weight Gain Before or During Your Period

Hormonal changes. So, why are you experiencing weight gain before your period? In the immortal words of Cady Heron: "This is all your water weight." And while Kalteen Bars aren't at fault, the hormone progesterone—essential in the early stages of pregnancy—is the one to blame. When there's no baby (aka when you get your period), your progesterone levels plummet, and as a side effect, each cell in your body retains an extra microscopic drop of water, explains Dr. Dardik. The result? Pre-period weight gain or water weight that can range from half of a pound to 10 pounds, usually averaging around five for most women, adds Dr. Dardik. (See also: Outsmart Your Hormones All Month Long (Plus 9 Surprising Things Making Your PMS Worse))

GI struggles. Hi, bloating. While it does not actually contribute to the changing numbers on the scale, bloating caused by gas can magnify the situation by making your stomach feel distended. But bloating isn't the only gastrointestinal problem to play a part in period weight gain. In fact, fluctuations in hormones (estrogen, progesterone, among others) before and during menstruation can also lead to constipation and/or diarrhea in many women, as Elana Maser, M.D., the director of the Women's Gastrointestinal Health Center at Mount Sinai Hospital, previously told Shape.

Research suggests that these changing hormone levels can impact the speed and function of the GI tract and, in turn, cause "prolonged transit" or, yup, constipation. And when you're super backed up, the number on the scale is understandably going to change—but only until you can finally get things a-go. Once your period is over, your period weight gain should gradually lessen. (Related: Is the Hype About the Squatty Potty Legit?)

Food cravings. As you approach the first day of your period, your body's busy riding a veritable hormonal rollercoaster that cuh-learly plays a major part in period weight gain. In addition to belly bloat and fluid retention, your changing hormones are also the reason for your serious sugar cravings, which, not shockingly, can also lead to weight gain before and during your period. There's no reason to starve yourself of treats when PMS-ing—just make sure to keep it in moderation, especially because cravings-caused period weight gain will not come off after your period, warns Dr. Dardik. (Although, if you're craving and eating salty foods, the sodium may be causing some of your bloating.)

How to Minimize Period Weight Gain

If you're set on weighing yourself regularly (and monitoring your period weight gain), you can weigh yourself once a week, on the same day, at the same time, using the same scale. "The main thing is not to overdo it because fluctuations in weight are common," says Dr. Dardik. If you're focusing on losing weight right now, consider looking at non-scale victories instead of the scale to measure progress.

If you want to manage your period weight gain and bloating, focus on maintaining your usual healthy behaviors, such as exercising and drinking a lot of water to help get rid of water retention, says Dr. Dardik. Also try to avoid fatty foods, alcohol, and salt, which triggers your body to hold onto water, says Dr. Dardik. (See also: The Best Foods for Cramps, Fatigue, Bloating, and More Period Symptoms)

Moral of the story: you can check your weight, but don't be paranoid about it. And keep your chin up: Your best days are ahead of you, explains Dr. Dardik, as women usually feel at their peak in the first 7-10 days after their period.