Excessive gas. What is normal and when to worry about wind

In a famous 1991 study, 10 healthy volunteers wore a small tube for 24 hours so scientists could collect every bit of wind they passed. They ate their normal diet plus 200 g (about 7 oz) of baked beans. The middle result was about 705 ml a day, close to 3 cups. Some passed nearly 1.5 litres. Everyone makes gas, and most of it is a sign that your gut bacteria are well fed.

So when does gas become excessive gas? In this guide I explain what is normal and what causes extra wind. I also share which foods and habits help, and the warning signs that mean you should see a doctor.

How much gas is normal?

Passing wind several times a day is normal, and passing it around 20 times on a high-fibre day can be normal too. In a 2014 Spanish study, 20 healthy adults on their usual diet passed wind about 7 times during the day. On a diet rich in beans and fibre, that rose to about 22 times.

A 2020 study of 63 healthy adults found a similar pattern. They passed wind about 9 times a day on their usual diet and about 21 times on a high-fibre challenge diet. So the number goes up and down with what you eat.

The 1991 study also found that people make less gas at night. Gas was still made during sleep, but at about half the daytime rate.

Where does gas come from?

Gas comes from two places, air you swallow and gas your gut bacteria make. Most wind comes from the bacteria in your large bowel. They ferment fibre and other carbs your body cannot digest, and they release gases as they feed.

Flatus is mainly made of 5 gases, nitrogen, oxygen, carbon dioxide, hydrogen and methane. In the 1991 study, a “fibre free” liquid diet for 2 days cut total gas to about 214 ml a day. It almost removed hydrogen. That tells us fermentation gases make up most normal wind.

Swallowed air mostly comes back up as burps. A 2026 review explains that swallowing too much air, called aerophagia, rarely causes symptoms on its own. Habits such as gulping drinks, chewing gum or eating fast can add to it.

Why is gas a sign of a healthy gut?

I strongly believe gas is often a sign your gut bacteria are doing their job. When clients come to me, I always ask about their gut health and their poop, and wind is part of that picture. A gut that makes no gas at all would usually mean very little fibre is reaching your bacteria.

Those bacteria turn fibre into short-chain fatty acids that help protect the gut lining. Cutting out all gas-making foods would also starve them. My guide to 30 plants a week explains why variety matters for these microbes.

The type of bacteria may matter too. A 2026 study from China found that people with frequent wind had fewer Faecalibacterium prausnitzii, a helpful bacterium that makes butyrate. In a placebo-controlled trial, one probiotic strain raised this bacterium and eased wind symptoms. This is early research with one strain, so it is not a reason to buy a supplement yet.

What causes excessive gas?

Excessive gas is usually caused by foods that ferment a lot, a sensitive gut, or a gut that struggles with certain sugars. Sometimes a health problem is behind it. Here are the most common causes.

• High-fibre and FODMAP foods. Beans, lentils, onion, garlic, wheat, cabbage and some fruits ferment quickly.
• A sudden jump in fibre. A 2022 review of 16 trials found fibre supplements caused more wind than control treatments.
• Lactose. Many adults digest milk sugar poorly. My guide to lactose and IBS explains how to test your own tolerance.
• Sugar alcohols. Sorbitol, mannitol and xylitol in sugar-free gum and sweets are common triggers. Read sorbitol and IBS for label tips.
• Constipation. Stool that sits in the bowel for longer has more time to ferment. My guide to constipation remedies can help.
• Swallowed air. Fizzy drinks, gum, smoking and eating fast add air.
• IBS, SIBO or coeliac disease. These can all cause extra wind and bloating, so they are worth checking with a doctor.

Do people with gas problems really make more gas?

Not always. Many people with gas problems make about the same amount of gas but feel it more. This was a surprising finding of the 2014 Spanish study.

The study compared 30 people who complained of wind with 20 healthy people. The patients passed wind about 22 times a day on their usual diet, compared with about 7. Yet after a test meal, both groups released almost the same volume of gas, about 260 ml in each group.

On a gas-making diet, the patients’ gut bacteria became less stable and less diverse. The healthy people’s bacteria stayed steady. The authors concluded that people with wind problems tolerate gas less well, and that this is linked with an unstable microbiome. In my view, this is why calming the gut matters as much as cutting foods.

Are beans really that bad for gas?

No, beans are not as bad as their reputation. This is one of the biggest gas myths. A 2011 report looked at 3 trials where adults ate half a cup of beans a day for 8 or 12 weeks.

Fewer than half reported more wind from pinto or baked beans in the first week. Only 19% noticed more wind with black-eyed peas. Between 3% and 11% reported more wind even on the control diets with no beans. The authors said worries about beans may be exaggerated, but people do vary.

If beans bother you, start with 2 to 3 tablespoons and build up. Canned and rinsed beans and lentils are often easier than dried ones. My guide to lentils and FODMAPs gives safe portions.

How can I reduce excessive gas?

You can reduce excessive gas by finding your trigger foods, building fibre slowly, eating more calmly and treating constipation. Most people do not need to give up healthy plant foods.

Try this

1. Keep a 1-week food and wind diary. Note what you eat and when wind or bloating is worst. Patterns often show up within days.
2. Build fibre slowly. Add one new high-fibre food every few days, not all at once. My guide to fibermaxxing explains how.
3. Test lactose. Try lactose-free milk or yogurt for 2 weeks and see if wind settles.
4. Cut sugar-free gum and sweets. They add both sugar alcohols and swallowed air.
5. Eat slowly and sip, do not gulp. Put your fork down between bites, and swap fizzy drinks for still water or herbal tea.
6. Keep your bowels moving. Two green kiwifruit a day and a toilet footstool help many people with constipation.
7. Move after meals. A gentle walk after eating may help gas pass. My guide to exercise for IBS has easy ideas.
8. Learn your gut signals. My Trigger or Safe game helps you spot common gassy foods.

Can a low FODMAP diet help with gas?

Yes, a low FODMAP diet can reduce wind, especially if you have IBS. In a 2014 Australian trial, 30 people with IBS ate a low FODMAP diet for 3 weeks. Bloating, pain and the passing of wind all fell compared with a typical Australian diet.

Low FODMAP is a short test, not a forever diet. You cut high-FODMAP foods for 2 to 6 weeks, then bring them back one by one to find your own triggers. My guide to the low FODMAP diet in 3 phases explains each step. A 2025 European expert consensus also lists low FODMAP and lactose-limiting diets among the options for bloating.

Do probiotics or fermented foods help with wind?

Some may help, but the evidence is still early. In the 2020 study of 63 healthy adults, a fermented milk with probiotics reduced daily wind by about 6 episodes on a high-fibre diet. It did not change the volume of gas, and there was no control group.

That study was run by researchers at a dairy company, so treat it with care. The 2025 European consensus lists probiotics and peppermint oil among options for bloating. My guides to probiotics for IBS and peppermint oil explain which ones have the best evidence.

Does stress make gas worse?

Stress can make you more aware of gas and bloating. Your gut and brain are wired together, and a stressed gut often feels every bubble. The 2025 European consensus says gut-directed hypnotherapy and cognitive behaviour therapy can help bloating in people with IBS.

For a simple daily habit, try my free 30-Day Calm Gut Challenge. You can also read how the gut-brain axis links stress and digestion.

When should I worry about gas?

Worry about gas when it comes with other symptoms, such as blood in your stool, weight loss, ongoing diarrhoea or severe pain. Gas on its own is rarely dangerous. A new pattern that does not settle deserves a check.

Losing 3 kg (about 7 lb) or more without trying is always worth a visit to your doctor. So is wind with greasy, pale stools that float, which can point to poor fat absorption. My guide to SIBO vs IBS explains other causes your doctor may check.

Frequently asked questions

Is passing wind 20 times a day normal?

It can be normal, especially on a day with lots of fibre, beans or vegetables. In research, healthy adults passed wind about 7 to 9 times a day on their usual diet. On a high-fibre diet, that rose to about 21 or 22 times. What matters more is whether it is new, painful or comes with other symptoms.

Why do I have so much gas all of a sudden?

A sudden rise in gas is often linked to a new food, more fibre, sugar-free products, a stomach bug or constipation. Think back over the past week for changes. If it lasts more than a few weeks or comes with warning signs, see your doctor.

What foods cause the most gas?

Beans, lentils, onion, garlic, wheat, cabbage, apples, milk for people who digest lactose poorly, and sugar-free sweets are common culprits. Everyone is different, though. A food diary or a guided low FODMAP diet is the best way to find your own triggers.

Should I stop eating fibre to stop gas?

No. Fibre feeds the gut bacteria that protect your gut lining and support your health. Cutting it out may reduce wind but harms your gut over time. Build fibre up slowly and choose gentler sources such as oats, kiwifruit and canned lentils.

Does holding in gas cause harm?

Holding in gas now and then is not dangerous, but it can make you feel bloated and uncomfortable. The gas does not disappear. It usually comes out later. Letting it pass when you can is kinder to your gut.

What I want you to remember

Gas is normal, and passing wind many times a day is part of a well-fed gut. Excessive gas usually links to certain foods, a jump in fibre, lactose, sugar alcohols, constipation or a sensitive gut. Many people with wind problems do not make more gas, they just feel it more.

Find your triggers, build fibre slowly, eat calmly and keep your bowels moving. See a doctor about blood, weight loss or a change that does not settle. If you have IBS, start with my complete IBS diet guide.