What causes bloating – and what actually helps

Bloating is one of the two most commonly reported gut symptoms, and most people experience it at some point.

It is also a symptom rather than a condition, which is why there is no single fix. A Mayo Clinic review of chronic bloating puts it bluntly: no treatment regimen has been consistently successful.

In this guide, we explain what causes bloating and which remedies have evidence behind them.

Highlights

• Bloating is the feeling of trapped gas, pressure and fullness. Distension is a measurable increase in the size of your abdomen. They often occur together and are not the same thing.
• A low FODMAP diet has the strongest evidence of anything you can try.
• A short walk measurably clears intestinal gas and reduces symptoms.
• Most of the popular remedies have little or no evidence, though several are harmless to try.

What causes bloating

Everyday causes account for most of it:

• Swallowed air: eating fast, drinking through a straw, chewing gum and fizzy drinks all put gas into your digestive system
• Constipation: the single most common cause, and the first thing to address
• Large meals: your stomach stretches to accommodate food, and more food means more stretch
• Salt: sodium makes the body retain water, which can produce a bloated feeling without any gas involved

Beyond those, a Mayo Clinic review  lists food intolerances, a previous gut infection that disturbed the microbiome, heightened sensitivity to normal gut sensations, slow intestinal transit, and abnormal reflexes between the gut and the abdominal wall.

Some foods are reliably gassy because gut bacteria ferment carbohydrates we cannot digest ourselves. Beans, lentils, broccoli, Brussels sprouts and cabbage are the usual suspects, as are the sugar alcohols in sugar-free gum and sweets, which appear on labels as sorbitol, xylitol and erythritol.

Bloating is also a symptom of celiac disease, irritable bowel syndrome, inflammatory bowel disease and lactose intolerance, which is why persistent bloating is worth investigating rather than managing.

What actually helps

The strongest evidence: a low FODMAP diet

FODMAPs are short-chain carbohydrates that the small intestine absorbs poorly, so they ferment further down and produce gas. They are found in wheat, onions, garlic, legumes, some fruits, dairy and the sugar alcohols above.

In a network meta-analysis of 13 trials covering 944 patients , a low FODMAP diet ranked first for bloating and distension severity, and beat standard dietary advice from NICE and the British Dietetic Association specifically for bloating.

Two caveats the authors raise. Most of those trials ran in specialist clinics rather than general practice, and they did not test the reintroduction phase. A low FODMAP diet is designed as a short elimination followed by structured reintroduction, not a permanent restriction, and it is worth doing with a dietitian.

Go for a walk

In patients with bloating , mild physical activity measurably increased intestinal gas clearance and reduced symptoms. This is the rare case where a simple remedy has a mechanism study behind it.

Fix constipation first

Bloating and constipation travel together, and treating the constipation often resolves the bloating. More fiber helps, but increase it over several weeks rather than at once, because a sudden jump produces more gas rather than less.

Eat slower and smaller

Eating quickly means swallowing more air, and it takes around 20 to 30 minutes for fullness signals to reach your brain, so fast eating also means more food. Smaller meals eaten more often put less stretch on the stomach.

Cut fizzy drinks

Carbonated drinks deliver gas directly into your digestive system. Some you burp back, the rest travels on.

Keep a food diary

Bloating triggers are individual, and two weeks of recording what you eat alongside how you feel will tell you more about your own triggers than any general list. It is also the only way to spot a genuine intolerance.

Worth trying, with weaker evidence

Peppermint oil beat placebo for IBS symptoms in a 2022 meta-analysis , though side effects were more common and the authors rate the quality of evidence as very low.

Probiotics may help. A 2023 review  found some strains and combinations beneficial in IBS, with certainty in the evidence rated low to very low across almost all analyses. If you try one, give it four weeks and stop if nothing changes.

What probably will not help

Lemon water, fennel seeds, pineapple and papaya enzymes, apple cider vinegar, abdominal massage and swapping white rice for brown are all widely recommended for bloating and none has meaningful evidence behind it.

Most are harmless, and if one works for you there is no reason to stop. But they are not the place to start, and a persistent problem will not be solved by any of them.

When to see a doctor

Bloating is usually benign. Book an appointment if it comes with:

• Weight loss you cannot explain
• Blood in your stool
• Persistent abdominal pain rather than discomfort that comes and goes
• A change in bowel habits lasting more than a few weeks
• Bloating that is new and persistent, particularly over the age of 50

Persistent bloating in women is also a recognized symptom of ovarian cancer, which is uncommon but frequently diagnosed late, so new and persistent bloating warrants a conversation rather than a remedy.

References

1. Black CJ, Staudacher HM, Ford AC. Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis. Gut 2022;71(6):1117–1126. PMID 34376515 . 13 randomised trials, 944 patients.
2. Villoria A, Serra J, Azpiroz F, Malagelada JR. Physical activity and intestinal gas clearance in patients with bloating. American Journal of Gastroenterology 2006;101(11):2552–2557. PMID 17029608
3. Lacy BE, Cangemi D, Vazquez-Roque M. Management of chronic abdominal distension and bloating. Clinical Gastroenterology and Hepatology 2021;19(2):219–231. PMID 32246999 . Review.
4. Ingrosso MR, Ianiro G, Nee J, et al. Systematic review and meta-analysis: efficacy of peppermint oil in irritable bowel syndrome. Alimentary Pharmacology and Therapeutics 2022;56(6):932–941. PMID 35942669
5. Goodoory VC, Khasawneh M, Black CJ, et al. Efficacy of probiotics in irritable bowel syndrome: systematic review and meta-analysis. Gastroenterology 2023;165(5):1206–1218. PMID 37541528

Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns and before undertaking a new healthcare regimen including making any dietary or lifestyle changes.