Weight gain on your period: Why it happens

It's normal for your weight to fluctuate during your cycle.
Written by
Gemma Kaczerepa
Reviewed by
Last updated on
June 3, 2024
min read
Weight Fluctuation: Do You Weigh More On Your Period? | Kin Fertility
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Clothes feeling a bit tighter during your period? Nope, it’s probably not your body playing tricks on you. It’s pretty normal for your weight to fluctuate throughout your monthly cycle, and for it to (temporarily) go up while you’re on your period.

Ever wondered what causes weight gain on your period, how long the extra weight sticks around, and if there’s anything you can do to manage it or avoid it entirely?

Here’s why it happens and what you can do about it.

Do you weigh more on your period?

Yep, you often do. In the week or so ahead of your period, it’s totally normal to weigh a bit more than usual and for your clothes to seem a little tighter. In fact, one study found that 65% of participants experienced swelling during their period — usually across the face, abdomen, pubic area, limbs and breasts [1].

Because the extra weight during your period is usually just water weight and not actual body fat, it’s only temporary. The weight usually appears in the days before your period and goes away about 3-5 days after you start bleeding.

And remember, just like many other symptoms of being on your period, like food cravings and low mood, not everyone gains weight in the lead-up. Whether you gain weight before your period, as well as how much you gain, is a completely personal thing.

How much weight gain is considered normal during your period?

While gaining weight is a common side effect of having your period, there’s no typical amount of weight gain and not a whole lot of research demonstrating what a normal range is.

Some women don’t gain weight at all. But, generally, a fluctuation of about 1.5-3kg more than your usual body weight is nothing to worry about. 

If you’re putting on more than that each month, reach out to your doctor to see if there’s another underlying issue causing it. Some medical conditions and medications can cause rapid, unexplained and persistent weight gain, which is why you’re best chatting with a medical professional [2].

What are other common period symptoms?

Besides putting on a bit of extra weight, you may notice a few other signs that your period is on its way [3][4][5]. Premenstrual symptoms include:

  • Digestive problems like diarrhoea or constipation
  • Bloating and gas
  • Headache
  • Hormonal acne
  • Hot flushes
  • Tender breasts
  • Joint pain
  • Fatigue
  • Low mood
  • Stress and anxiety
  • Irritability
  • Changes in appetite — often increased hunger
  • Food cravings
  • Insomnia
  • Decreased libido

What causes period weight gain?

So, what’s the reason for period weight gain? There’s no single underlying cause, but several explanations as to why you might put on weight in the phase before your period.

Hormonal fluctuations

There’s a lot going on hormonally when you’re about to get your period. The hormones oestrogen and progesterone are 2 of the most important components of your menstrual cycle, helping to regulate your period and prepare your body for a possible pregnancy.

Levels of both hormones go up significantly in the weeks before your period, which can contribute to fluid retention. This is because they help relax your blood vessels and boost salt retention, leading to increased — but short-term — water storage. 

Cravings and eating differently

Progesterone can also stimulate your appetite, which is why you might find yourself feeling hungrier in the days before your period. Progesterone levels are at their highest about a week prior, so that may be when you experience a noticeable increase in appetite [6].

Magnesium levels also drop shortly before your period, which can trigger sugar cravings and make you feel thirsty. Sometimes, thirst can be mistaken for hunger, leading you to eat more.

Plus, PMS is well-known for being a time of stress and low mood. And what better way to soothe the period blues than by munching on chocolate, chips and ice cream? 

Many of us turn to comfort foods ahead of our period, which can also contribute to water retention — especially foods that are high in salt. So, that premenstrual weight gain could also simply be down to a temporary change in diet.

Skipping workouts

If you’re feeling lethargic, low and struggling to get a good night’s sleep ahead of your period, it’s completely understandable that you’d want to give your morning jog a miss. The same goes if you’ve got period pain like abdominal cramps or aches and pains in your joints. 

Deviating from your usual exercise routine could be another explanation as to why you’re a little heavier before your period. 


Ever noticed that you’re not emptying your bowels as often in the lead-up to your period? Increased progesterone can cause slower digestion, which is why constipation is a common side effect. The result can be abdominal bloat, which is where your tummy is tighter and more swollen.

It’s worth noting that bloat isn’t really a true form of weight gain, but it can make you feel like your clothes are tighter than usual.

How to help reduce period weight gain

While there’s no guarantee you can completely prevent weight gain during your period, there are a few things you can do to at least minimise it. Here are our top tips.

Maintain your H20 intake

It might seem completely illogical to drink more water when your body is already storing a lot of it. But make sure to maintain adequate water intake before and during your period, as this helps reduce salt and water retention.

When you’re dehydrated, your body holds on to more fluid as a way to combat the excess salt it’s dealing with. On the flip side, drinking plenty of water will help to flush the salts from your system.

Aim for about 9 cups of water per day, or 13 cups if you’re breastfeeding [7].

Try to stick to healthy foods

As tempting as it can be to reach for sweet and salty foods when you’re on your period, remember that they can contribute to temporary weight gain — particularly high-salt foods. Instead, see if you can swap out the chocolate and chips for more nutritious options. 

Keep fruits, yoghurt, raw nuts and protein bars on hand for snacking. If you absolutely can’t go without salt, consider moderating your salt intake by going for lightly salted popcorn over heavily salted chips. 

Make sure your meals contain calcium and complex carbs (think things like wholemeal bread and pasta, brown rice and beans), both of which can help reduce PMS symptoms [8].

You might find that these foods help to reduce cravings, too, as they don’t cause the same insulin spikes as high-sugar and highly processed foods.

Keep exercising

We get it: working out when you’re dealing with PMS symptoms can be nothing if not taxing. But even if you go for a 30-minute brisk walk around the block, you might be able to combat some of the nasty side effects of being on your period.

First up, exercise moves excess fluids around your body, potentially reducing water retention. If you manage to break a sweat, you might be able to shed even more water. Second, exercise releases endorphins, which can make you feel good if you’re dealing with a low mood.

Give a gut-loving formula a go

If you’re experiencing digestive woes like constipation, a digestive health supplement — like a probiotic — can help get things moving and relieve the discomfort and swelling associated with bloating.

Kin’s Daily Digest is a great option, containing pre and probiotics, fibre and digestive enzymes to keep your gut in tip-top shape (and make it less likely to suffer from period-induced constipation). 

The Daily Digest also includes patented probiotics that support your mental well-being through the gut-brain axis, which may also help to relieve some of the emotional side effects of PMS. 

Consider a PMS supplement

If you’d prefer a supplement that addresses PMS in its entirety, Kin’s Hormone Harmony might just be the solution you’re looking for. 

The Hormone Harmony is made up of an effective mix of natural ingredients designed to alleviate many of the common symptoms of PMS, including cramps and mood swings. 

It also contains magnesium (which we know is a crucial player in regulating your appetite on your period) and Gymnema, an Australian native used in Ayurvedic medicine to help combat sugar cravings, which could be very beneficial if you’re trying to curb your consumption of sugary foods.

If weight is an issue, jump on board a weight loss program

Your weight might only fluctuate minorly and temporarily around your period, but if it's an overall issue you want to get on top of, think about joining a dedicated weight loss program like Juniper’s Weight Reset Program.

Rather than demanding you crash diet or kickstart an impossible-to-maintain exercise regimen, the Weight Reset Program helps you lose weight holistically and sustainably — and keep it off.

You’ll have the support of dietitians and health coaches who look at everything from nutrition and exercise to sleep and stress, access to a private weight loss community, health tracking to log your goals and measure your successes, and GP-prescribed medication to curb cravings and improve your metabolic function.

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