Why am I bloated?

Bloating is one of the most-Googled gut questions in the UK, and most of the advice online treats it like one thing. It is not. Bloating is a final signal with three different upstream causes. Once you know which one is yours, the fix gets a lot more obvious.

1. Gas bloating. Your gut bacteria are fermenting something they don't love, usually a fibre type or a food group. The bloat is in the lower belly, and there's wind. It often peaks two to four hours after a meal.
2. Water bloating. Sodium, hormones, or a high-carb meal pulls water into your tissue. The bloat is generalised and a bit puffy, often with rings feeling tight. Most pre-period bloating is this.
3. Slow-movement bloating. Food is sitting in your stomach or colon longer than it should. The bloat starts higher up, soon after eating, and you feel full quickly. Constipation, GLP-1 injections, or low stomach acid can all do this.

The single biggest gas trigger in adults is the FODMAP family of carbohydrates. These are short-chain fermentable sugars in foods like onion, garlic, wheat, apples, pears, lentils and milk. Your gut bacteria love them and produce a lot of gas while breaking them down. Some people tolerate them fine, others bloat hard.

The Monash low-FODMAP diet is the gold-standard test. It runs for two to six weeks of strict elimination, then a structured reintroduction so you find your specific triggers. It is not a forever diet. The point is to learn what your gut reacts to.

Quick wins before going full FODMAP: cut onion and garlic for a week. Swap your protein bar (often sweetened with inulin or chicory root, both heavy fermenters). Try lactose-free milk for seven days. Walk for 15 minutes after meals to help wind move through.

Water bloating is the body holding extra fluid in your tissue rather than circulating it. It is almost never about how much you're drinking. Drinking less makes it worse, because your body holds on tighter when it senses you're underhydrated.

The usual triggers are sodium load (a salty restaurant meal will puff you up overnight), hormonal shifts (the luteal phase of the cycle is the classic), high-carb meals (glycogen stored in muscle holds roughly three grams of water per gram of glycogen), and inflammation from poor sleep or alcohol.

What helps: salt down for 24 to 48 hours, water up to 2 to 2.5 litres, magnesium and potassium-rich foods (avocado, leafy greens, banana), light cardio. It usually resolves on its own in a day or two.

If you feel bloated within an hour of eating and you fill up fast, food is moving slowly out of your stomach. The most common reasons in 2026 are GLP-1 injections (they work partly by slowing stomach emptying), low stomach acid (more common with age, stress, and some acid-reducing medicines), and constipation backing up the whole system.

• Smaller, more frequent meals: four light meals beat two big ones if you're on a GLP-1.
• Ginger before meals: trials have studied it for helping the stomach empty faster, with modest effects (Wu 2008). A pharmacist can advise if you take other medicines.
• Walk for 10 to 15 minutes after eating. Skip lying down.
• If constipation is the root, fix that first. Bloating clears once the bottom of the system is moving.

Most bloating is a pattern you can read and adjust. A few things sit outside that: blood in your stool, losing weight without trying, persistent pain on one side, a change in bowel habit that has not settled, or bloating that is there most days and refuses to shift with any of the usual fixes. None of these means disaster, and all of them mean the same thing: this is the point to stop self-managing and have a conversation with your doctor, whatever your age. For women especially, UK guidance takes persistent bloating seriously in its own right: distension most days, feeling full quickly, pelvic or tummy pain, or needing to wee more often are each reason for a doctor to take a proper look, and there is no age cut-off on that advice (NICE NG12).

• Activated charcoal pills. The human evidence is mixed: some trials show reduced gas and bloating symptoms, others show no benefit on gas at all.
• 'Detox' teas. Most are stimulant laxatives that empty your colon, which feels like debloating but isn't.
• Cutting all fibre. Some people do react to fibre changes, but a long-term low-fibre diet makes the underlying microbiome problem worse.
• Drinking more water 'to flush'. Helpful for water bloat, useless for gas bloat.