Bloating before your period: what to eat and what actually helps

Feeling puffy, tight or swollen in the days before your period is one of the most familiar premenstrual symptoms. The Royal College of Obstetricians and Gynaecologists says nearly all women have some premenstrual symptoms, and both the NHS and the RCOG list bloating among them.

The short answer: a few simple food and drink habits can ease it, the evidence for some is stronger than others, and bloating that sticks around most of the month is worth checking with a GP.

The short version

• Eat smaller, more frequent meals in the week before your period
• Go easy on salt, fizzy drinks and alcohol
• Get enough calcium, from food first
• Keep moving: regular exercise helps PMS symptoms overall
• See a GP if you feel bloated regularly, not just before your period

Why do you get bloated before your period?

Two things seem to be going on. First, your body holds on to a little more fluid. A year-long study that tracked women through their cycles found fluid retention peaked, on average, on the first day of bleeding (White et al., 2011).

Second, digestion may slow down. In the luteal phase, the second half of your cycle when progesterone is high, food has been found to move through the gut more slowly (Wald et al., 1981), although not every study has found the same. Slower digestion can mean more wind and constipation, which feels like bloating.

Gut symptoms around periods are common in general. In a study of 156 healthy women, 73% had at least one digestive symptom before or during their period (Bernstein et al., 2014). People with IBS often notice bloating and pain get worse around their period, possibly because of prostaglandins, the same chemicals behind period cramps (Bharadwaj et al., 2015).

Expert picks: what to read next

• Craving sugar in the same week? Here's why premenstrual cravings happen and the habits that take the edge off.
• Thinking about magnesium? Here's what the research actually supports, and where it falls short.

What should you eat to reduce bloating before your period?

No single food switches bloating off, but the evidence points to a handful of habits worth trying in the week before your period.

1. Eat smaller, more frequent meals

For PMS, the NHS suggests "you may find eating frequent smaller meals every 2 to 3 hours better". Large meals stretch a gut that may already be moving more slowly, so spreading food across the day can help you feel less full and tight.

2. Cut back on salt

Salt makes your body hold on to water. In a controlled feeding trial of 412 adults, eating a high-salt diet raised the risk of bloating by 27% compared with a low-salt diet (Peng et al., 2019). That trial wasn't about periods, but it's an easy thing to try. Most salt hides in ready meals, crisps, processed meat, bread and stock cubes rather than the salt shaker.

3. Get enough calcium

Calcium has some of the strongest evidence for premenstrual symptoms. In a randomised trial of 466 women, 1,200mg of calcium a day reduced overall symptoms by 48% by the third cycle, compared with 30% on a placebo, and water retention improved too (Thys-Jacobs et al., 1998).

Dairy, fortified plant milks, calcium-set tofu, tinned fish with soft bones and green leafy vegetables are good food sources. Speak to a GP or pharmacist before starting a supplement.

4. Consider magnesium

A small trial of 38 women found 200mg of magnesium a day eased fluid-retention symptoms, including abdominal bloating, but only in the second month of taking it (Walker et al., 1998). It's a small study, so think of magnesium as worth trying rather than proven. Nuts, seeds, beans, wholegrains and leafy greens are rich in it.

5. Swap fizzy drinks and alcohol for water

The NHS advice for bloating is not to drink lots of fizzy drinks, alcohol or caffeine. For gut symptoms like IBS, it recommends at least 8 to 10 drinks of fluid a day, around 1.5 litres. Drinking enough also helps prevent constipation, which makes bloating worse.

6. If you're constipated, try soluble fibre

If a slower gut leaves you constipated, the NHS suggests soluble fibre such as oats or linseed, so porridge for breakfast is an easy start. More fibre doesn't suit everyone, though: in the same salt trial, the higher-fibre diet also increased bloating (Peng et al., 2019). If extra fibre makes you feel worse, scale it back.

Do vitamin B6 or other supplements help?

A review of trials found vitamin B6 may help overall PMS symptoms, but the trials were low quality and didn't look at bloating on its own (Wyatt et al., 1999). The NHS lists vitamin B6, calcium, vitamin D and magnesium as options, but says there is "not much evidence that they work". Check with a GP or pharmacist first, especially if you take other medicines.

Does exercise help with period bloating?

Probably. A review of randomised trials found regular exercise reduced PMS symptoms, with the biggest effect on physical symptoms, although most of the trials had a high risk of bias (Pearce et al., 2020). The NHS also recommends regular exercise to improve digestion and help prevent bloating. A brisk walk counts.

Is bloating a sign of perimenopause?

It can be part of it. Bloating isn't on the NHS list of menopause symptoms, but in a survey of around 600 UK women aged 44 to 73, presented by The Menopause Society in 2025, 77% reported bloating and 82% said their gut symptoms started or got worse around perimenopause or menopause. That's an early, not yet peer-reviewed finding. The habits above are a sensible starting point, and the advice on when to see a doctor applies at any age.

When should you see a doctor about bloating?

Bloating that comes and goes with your period is usually nothing to worry about. The NHS says to see a GP if you feel bloated regularly, or if bloating comes with weight loss you can't explain or blood in your poo.

The NHS also says that having a swollen tummy or feeling bloated frequently, roughly 12 or more times a month, can be a symptom of ovarian cancer. See a GP if that sounds like you, especially if it isn't going away or is getting worse. It's far more likely to be something else, but it should always be checked.

And if premenstrual symptoms are severe enough to stop you getting on with daily life, which the RCOG says happens to between 2 and 4 in 100 women, it's worth speaking to a doctor too.

The takeaway

Period bloating comes from extra fluid and a slower gut in the days before your period. Smaller meals, less salt, fewer fizzy drinks and enough calcium are the best-supported places to start, with magnesium and regular exercise as useful extras. Bloating that happens most of the month needs a GP, not a diet change.

Frequently asked questions

How long does period bloating last?

It varies from person to person. Studies that track fluid retention across the cycle found it peaks, on average, on the first day of your period. If bloating carries on well after your period, or happens on most days of the month, see a GP.

What is the best drink for bloating before your period?

Water. The NHS advises against drinking lots of fizzy drinks, alcohol or caffeine when you're bloated, and drinking enough fluid helps prevent constipation, which can make bloating worse.

Can calcium help with bloating before your period?

It may. In a randomised trial of 466 women, 1,200mg of calcium a day reduced premenstrual symptoms, including water retention, more than a placebo. Food sources such as dairy, fortified plant milks and calcium-set tofu are a good first step.

Does salt make period bloating worse?

Salt makes your body hold on to water, and in a controlled trial a high-salt diet raised the risk of bloating by 27% compared with a low-salt diet. Cutting back on processed and ready-made food is the easiest way to eat less salt.

When is bloating a sign of something serious?

See a GP if you feel bloated regularly, not just before your period, or if bloating comes with unexplained weight loss or blood in your poo. The NHS says feeling bloated roughly 12 or more times a month can be a symptom of ovarian cancer and should be checked.