Why Do I Gain Weight During My Period?

You may notice that, along with the other changes your monthly cycle brings, you experience weight gain during your period. Your menstrual cycle and weight fluctuation go hand in hand, but weight gain this time of the month is often the result of water retention and usually isn't permanent.

Even if you take steps to reduce bloating during your period, other hormones affecting weight can play a role in appetite, energy levels, and of course, mood - all of which can affect your food choices and activity levels this time of the month and contribute to unintended weight gain.

If you're prone to weight gain during your period, read on to discover what experts say about exercise during menstruation, the best diet for PMS, period bloating remedies, and more.

What Causes Weight Gain During Your Period?

Changing levels of the hormones that control your menstrual cycle, mainly estrogen and progesterone, affect weight. One study found that women gained a pound, on average, during their cycle, likely because of water retention (more on that below).

Some women can gain as much as five pounds, says Suzy Lipinski, MD , a board-certified obstetrician-gynecologist and the medical director at Pediatrix Medical Group in Colorado.

Below are some common causes of period-related weight gain, according to experts and research.

Increased Appetite and Cravings

Period cravings aren't just a rom-com trope - the cliché of needing chocolate during that time of the month can be attributed to the roller coaster that progesterone and estrogen ride during your cycle. "During the luteal phase, just before menstruation, increased progesterone levels can lead to heightened appetite, often resulting in cravings for high-calorie sugary comfort foods," says Aderet Dana Hoch, RDN , the owner of Dining With Nature in New York City. "This phase may also slightly boost metabolic rate, prompting the body to seek more energy."

Also, estrogen and serotonin (the mood-regulating hormone) are closely related, and when estrogen levels fluctuate between the luteal phase and menstruation, serotonin can, too, which can lead you to crave sugary delights or comforting carbs in an attempt to temporarily feel better, Dr. Lipinski says.

"There is some speculation that cravings for carbohydrate-rich foods are driven by the body's desire for tryptophan, a precursor to serotonin," says Angel Luk, RD , the author of You Can't Out-Train a Bad Diet . Then, serotonin levels may rise, resulting in improved mood.

Fortunately, balance is usually restored later in the cycle. "During the follicular phase leading up to ovulation, elevated estrogen levels can suppress appetite by increasing the production of leptin, the satiety hormone, and reducing ghrelin, the hunger hormone," says Hoch.

Menstrual Water Retention

Bloating and swelling are most common right before ovulation when estrogen levels peak, says Nicole Ibarra, RD , the founder of Altitude Nutrition & Fitness in Redding, California. That's because high estrogen signals the production of aldosterone, a hormone made in the kidneys that causes salt and fluid retention. Once again, that switch is flipped with the next phase of the cycle. "When menstruation begins, you may notice a decrease in retention and the diuretic effect of progesterone," says Hoch. "Individual tendencies, as well as diet and lifestyle, can also influence these effects.

Skipping Workouts

It's common to feel sluggish before or during your period, and, understandably, this can lead you to skip workouts. Low energy during menstruation is at least partially due to loss of blood, which also means loss of iron, a key building block of blood that is an essential transporter of oxygen throughout the body, says Lipinski. "Heavy flow in particular can cause low blood counts, which may leave you fatigued and short of breath," she says.

Anyone who has iron deficiency anemia or is at higher risk for low iron, such as plant-based eaters, should consult their healthcare provider about whether an iron supplement is beneficial to offset monthly menstrual blood flow.

GI Issues

Research suggests that as many as 73 percent of people with menstrual cycles experience GI symptoms in the days leading up to their period, including constipation, bloating, diarrhea, and nausea.

The two main players in gastrointestinal period stuff are progesterone and prostaglandins. Progesterone, when at its height during ovulation, can cause constipation because it slows down digestion and can make it harder to have regular bowel movements, says Eve Lepage, RN, a fertility nurse with Clue, the period tracking app. Some people experience constipation before their period, while others may deal with it during the first few days of bleeding."

Prostaglandins, the inflammatory chemicals produced during a period that help the uterus contract and shed its lining, can have the opposite effect. "They cause digested food in your gastrointestinal tract to move faster than usual," Lepage says, which explains why you may have to go more often during the first couple days of your period. Prostaglandins also cause diarrhea and cramping, Lipinski adds.

Because everybody is different, exactly when these symptoms pop up can vary from person to person. One study examined more than 33,000 menstrual cycles to explore how GI symptoms fluctuate across them.

"Findings revealed that GI issues like constipation, bloating, diarrhea, and nausea are significantly more common during the luteal phase (just before menstruation) than in the follicular phase," says Lepage. "These symptoms were present in both individuals with and without premenstrual syndrome (PMS), but those with PMS experienced more severe GI issues."

The study also highlighted a strong connection between mood symptoms and GI symptoms. People who reported mood disturbances - such as anxiety, irritability, or depression - were more likely to experience worsened GI symptoms, whether or not they had PMS. An association between mood and gut function was consistent across both the luteal and follicular phases.

How to Manage Weight Gain During Your Period

Gaining up to five pounds by the end of your cycle is normal, says Lipinski. If that increase exceeds seven pounds or weight gain persists after your period ends, a talk with your doctor is warranted. There are things you can do to minimize period-related weight gain.

How Diet Can Fight Weight Gain During Your Period

Experts recommend these tips to manage symptoms of menstruation, including weight gain.

• Drink water. Proper hydration will flush excess sodium and actually counteract water retention, says Lepage.
• Get enough vitamin D and magnesium. A study that examined the impact of vitamin D levels on PMS symptoms found that participants with the highest vitamin D intake at 706 IU per day were associated with a 41 percent reduction in PMS symptoms. The study subjects were deficient in vitamin D, however, so it is unclear whether the same results would be seen in people with normal levels.
  Foods rich in vitamin D include mushrooms, fish, and dairy. Magnesium is necessary to help with bowel function and relax muscles, says Lipinski. There is some research indicating that magnesium may modulate period weight gain from fluid retention; however, there is inadequate evidence to recommend magnesium supplementation, says Luk.
  Instead, it's best to fill up on magnesium-rich foods like spinach, chia seeds, dark chocolate, avocado, quinoa, or nuts.
• Avoid excess sugar, alcohol, and salty food. All of these can contribute to bloating and fluid-retention, Lipinski says.
• Eat a balanced diet. "While the Mediterranean diet is not specially named in the treatment of menstrual weight gain, foods that provide key nutrients may reduce menstrual symptoms overall, including but not limited to anxiety, irritability, forgetfulness, swelling, and bloating," Luk says. The best diet for PMS includes dark green leafy vegetables (which have many minerals including calcium and magnesium); nuts, whole grains, beans, and legumes (all plant-based proteins with plenty of fiber), and fatty fish like salmon (a good source of vitamin D).

Managing Period Weight Gain Through Exercise

Aerobic exercise like walking, cycling, or light cardio has been shown to decrease PMS symptoms by reducing bloating, headache, diarrhea, and increased appetite.

Lipinski adds that yoga, specifically, can help with cramps - and one study found that five basic poses including Cat-Cow, Child's pose, Downward Dog, plank, and Cobra decreased participants' menstrual pain, so it's worth stretching it out, even if you have to go slowly.

The Takeaway

It's totally normal to gain a few pounds before or during your period, or feel generally off and bloated. These changes are usually not permanent, but if you are prone to weight gain during your period, you can help mediate those changes with diet and exercise. Good hydration, a balanced diet that includes foods rich in magnesium, vitamin D, potassium, and other key nutrients, and slow, gentle workouts may all help with weight gain and other unpleasant changes during your cycle.

Editorial Sources and Fact-Checking

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy . We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Sources

1. Kanellakis S et al. Changes in body weight and body composition during the menstrual cycle. American Journal of Human Biology . July 23, 2023.
2. Souza LB et al. Do Food Intake and Food Cravings Change During the Menstrual Cycle of Young Women? Revista Brasileira de Ginecologia e Obstetrícia . November 28, 2018.
3. Sayegh R et al. The effect of a carbohydrate-rich beverage on mood, appetite, and cognitive function in women with premenstrual syndrome. Obstetrics and Gynecology . October 1995.
4. Szmuilowicz ED et al. Relationship between aldosterone and progesterone in the human menstrual cycle. Journal of Clinical Endocrinology & Metabolism . July 25, 2006.
5. Bernstein MT et al. Gastrointestinal symptoms before and during menses in healthy women. BMC Women's Health . January 22, 2014.
6. Hannan K et al. Mood symptoms and gut function across the menstrual cycle in individuals with premenstrual syndrome. Hormones and Behavior . November 2024.
7. Heidari H et al. Vitamin D Supplementation for Premenstrual Syndrome-Related Inflammation and Antioxidant Markers in Students With Vitamin D Deficient: A Randomized Clinical Trial. Scientific Reports . October 17, 2019.
8. Walker AF et al. Magnesium Supplementation Alleviates Premenstrual Symptoms of Fluid Retention. Journal of Women's Health . April 25, 2009.
9. Dehnavi ZM et al. The effect of 8 weeks aerobic exercise on severity of physical symptoms of premenstrual syndrome: A clinical trial study. BMC Women's Health . May 31, 2018.
10. Tsai SY. Effect of Yoga Exercise on Premenstrual Symptoms among Female Employees in Taiwan. International Journal of Environmental Research and Public Health . July 16, 2016.

Meet Our Experts See Our Editorial Policy Meet Our Health Expert Network

Kara Smythe, MD

Medical Reviewer

Kara Smythe, MD, has been working in sexual and reproductive health for over 10 years. Dr. Smythe is a board-certified fellow of the American College of Obstetricians and Gynecologists, and her interests include improving maternal health, ensuring access to contraception, and promoting sexual health.

She graduated magna cum laude from Florida International University with a bachelor's degree in biology and earned her medical degree from St. George's University in Grenada. She completed her residency in obstetrics and gynecology at the SUNY Downstate Medical Center in Brooklyn, New York. She worked in Maine for six years, where she had the privilege of caring for an underserved population.

Smythe is also passionate about the ways that public health policies shape individual health outcomes. She has a master's degree in population health from University College London and recently completed a social science research methods master's degree at Cardiff University. She is currently working on her PhD in medical sociology. Her research examines people's experiences of accessing, using, and discontinuing long-acting reversible contraception.

When she's not working, Smythe enjoys dancing, photography, and spending time with her family and her cat, Finnegan.

See full bio

Kayla Blanton

Author

Kayla Blanton is a Cincinnati-based freelance writer who covers a range of lifestyle topics, including health, wellness, food, beauty, and entertainment. Her work has been featured on Prevention.com, MensHealth.com, Bustle, and Eat This, Not That, among other outlets.

She received a bachelor's degree in journalism from the E.W. Scripps School of Journalism at Ohio University, with specializations in public health and women, gender, and sexuality studies.

See full bio See Our Editorial Policy Meet Our Health Expert Network