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Do You Gain Weight On Your Period? Here's Why.

woman gaining weight on her period

Do You Gain Weight On Your Period? Here's Why.

You've probably heard that some women gain weight on their periods. It's not a myth, it's true. But how does this happen? And why does it happen to only some women, not all?

Here's what you need to know about period weight gain and how it affects your body.

Why do you gain weight on your period?

  • Hormonal changes: One of the most common causes of weight gain during your period is fluctuations in hormone levels, which can cause fluid retention and bloating in some women. Right before your period, the female sex hormone (oestrogen) peaks, says Mary Jane Minkin, MD, a clinical professor of obstetrics, gynaecology, and reproductive sciences at the Yale School of Medicine. High levels of oestrogen can make you feel bloated and cause you to gain a few pounds of water weight.
  • Low blood sugar levels: If you're experiencing symptoms such as fatigue or irritability during your cycle (and especially if these symptoms occur just before or at the beginning of your period), eating fewer carbs could help prevent unwanted pounds from packing on during this time.
  • Water retention: Most weight gain during a period is down to water retention, says Lauren Streicher, MD, a clinical professor of obstetrics and gynaecology at Northwestern University Feinberg School of Medicine and the medical director of the Center for Sexual Medicine and Menopause at Northwestern Memorial Hospital. “You retain a lot of fluid when your period comes, and then the weight goes away afterwards," she says. This can lead to uncomfortable bloating before and during periods, often described as feeling sore and swollen. 
  • PCOS (polycystic ovarian syndrome): If you have PCOS, a hormone imbalance may cause insulin resistance and high levels of insulin in the body--which makes it difficult for fat cells to burn energy as fuel instead of storing it as fat tissue. The result? Weight gain!
  • Overeating: Sometimes it's just plain old overeating at work here. When menstruating, the increase in progesterone levels can cause an increase in food cravings or PMS symptoms like irritability or depression that make us feel hungry and reach for comfort foods like chocolate cake (or ice cream). If you're trying to control bloating or weight gain, make sure you stay hydrated, and when sugar cravings strike, go for fruits instead, which have natural sugars.

How much weight do you gain on your period?

The amount of weight you gain on your period varies from person to person. Some women gain as much as five pounds, while others only gain two or three pounds. The main cause is water retention, which is especially common in women who exercise regularly.

It's not unusual for weight gain to vary between different women and cycles, says Charis Chambers, MD, a gynaecologist in Houston, US. "An average adult has weight fluctuations of up to five pounds in a single day, so it is safe to say that weight changes within that range are normal," Dr. Chambers says.

If you're worried about weight gain, try to eat healthy foods and avoid junk food as much as possible. This will help keep your weight down and keep you feeling good throughout the rest of your cycle!

Can you eat more on your period without gaining weight?

Yes, you can eat more on your period without gaining weight. But it's important to be careful not to overindulge.

How much is too much? It depends on your body type and metabolism. If you are naturally thin and have a fast metabolism, then eating more than usual might not cause any extra weight gain at all. But if you're already overweight or have a slower metabolism, then eating even just a little bit more than usual could lead to some extra pounds in no time!

When does period weight gain start?

Weight gain on your period is temporary and goes away after your period ends. It will usually show up in the week leading up to your period, during your period, or just after your period.

Weight gain before your period starts

You may gain weight before your period even begins. This can happen if you're eating more than usual and not exercising as much, which leads to water retention, bloating and swelling in the body.

Weight gain during your period

Some women experience a drop in their metabolism during their cycle, because of hormonal changes that affect how the body uses energy (calories). This means that even if you're eating less than normal during this time, it's possible to still pack on pounds from excess fluid retention and bloating caused by PMS symptoms, such as cramps or mood swings — not necessarily from overeating!

Weight gain after your period ends

The good news is that when your period ends, so does an increase in calorie burn. This means that most likely any weight gained during your period should come off again after bleeding stops completely.

When does period weight gain go away?

Weight gain on your period is temporary, but it can take some time to go away. Weight gain on your period is caused by water retention, so once your body flushes out the extra fluid, you'll be back to normal.

If you're only gaining a few pounds and they're going away after your period ends, then there's no need to stress about it! It's likely just water weight and nothing more serious, like PCOS (polycystic ovary syndrome).

Is there anything I can do to make period weight gain go away quickly?

Reduce stress levels

There are many ways of practicing mindfulness, but one simple method involves focusing on all the sensations in your body at any moment — and then letting them go when they pass away. This practice can help reduce stress levels overall, which may also reduce bloating caused by PMS or menstrual cramps, and keep hunger pangs at bay!

Eat well

Eat well: You should be eating healthy, balanced meals throughout your cycle. But if you're concerned about gaining weight during your period, it's especially important to make sure you're getting enough fibre and fluids to avoid constipation. Avoiding salty foods and caffeine is also a great idea if you're feeling bloated during your period.


Do some more exercise to reduce water retention. Water weight makes up most of the additional pounds on your body during your period. If you're exercising regularly and eating well, but still notice an increase in weight during this time of the month, try doing more physical activity, practice yoga, and drink lots of water before bedtime (to encourage flushing).

Stay hydrated

You can do a few things to reduce your water retention, which is what causes most of the period bloating. First and foremost, make sure you're drinking enough water during this time. Drinking plenty of extra water will help flush out excess salt from your system and keep your body hydrated throughout the day.

Stay comfortable

If you're feeling bloated during your period, the best thing you can do is stay comfortable. Wearing comfortable and breathable period protection like our period underwear will allow you to feel confident, knowing that you're leak free and protected during the day. Our new One Size period pants stretch with your body, with one pair covering four sizes, making them the perfect pants for bloating. Why not give them a try?

Is it normal to gain weight on your period?

It is normal to gain weight on your period. Many women, especially those who are not used to having their periods or those who have just started having them, are worried they will gain weight. As a result, they might stop eating during their menstrual cycle and this can cause other problems, such as low energy levels and headaches. A great way to keep track of weight gain during your period is by using a period tracker, such as Flo.

5 things to remember:

  1. It is normal to gain weight before and during your period.
  2. The average woman can gain anywhere between 1 and 5 pounds during a menstrual cycle.
  3. Period weight gain is a common PMS symptom caused by hormonal fluctuations, sometimes due to water retention, overeating due to stress, or increased cravings.
  4. Period weight gain usually goes away a couple of days after your period ends.
  5. There are things you can do to reduce period bloating and weight gain, including exercising, eating well, staying hydrated, and reducing your stress levels.

The takeaway

So there you have it — yes, your period does make you gain weight, but there are some things that you can do to take control back. We hope this article has helped you understand why you may gain weight during your period. Feel free to ask any questions or share your own experience with period bloating or gaining weight on your period in the comments below. As always, if you're concerned, speak to your doctor!

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