What Causes Bloating After Eating? Common Triggers and What to Do

What is bloating, exactly?

Bloating is a feeling of fullness, tightness, or swelling in the abdomen, often after eating. It can be accompanied by visible distension (your stomach physically pushing out), excess wind, and discomfort. According to the NHS, up to 1 in 5 people in the UK experience bloating regularly.

It's worth distinguishing between bloating (the sensation of pressure or fullness) and distension (a measurable increase in abdominal girth). You can feel bloated without visible swelling, and some people experience distension without much discomfort. Both are usually caused by the same underlying mechanisms.

Most bloating is caused by gas — either swallowed air or gas produced by bacteria fermenting food in the large intestine. The good news is that in most cases, the triggers are identifiable and manageable.

The most common causes of bloating after eating

1. High-FODMAP foods

FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) are short-chain carbohydrates that are poorly absorbed in the small intestine. When they reach the large intestine, gut bacteria ferment them rapidly, producing gas — and that gas causes bloating.

The low-FODMAP diet was developed by researchers at Monash University in Melbourne and has become the gold-standard dietary approach for managing bloating and irritable bowel syndrome (IBS). According to Monash's research, around 75% of people with IBS experience significant symptom improvement on a low-FODMAP diet.

Not everyone needs to avoid FODMAPs permanently. The approach involves a structured elimination phase (2-6 weeks), followed by systematic reintroduction to identify which specific FODMAPs cause problems for you. A dietitian can guide this process. For more detail on tracking what triggers your symptoms, see our guide on how to track food intolerances.

2. Eating too quickly

When you eat fast, you swallow more air (a process called aerophagia). This trapped air accumulates in the stomach and intestines, causing bloating and belching. The British Dietetic Association recommends taking at least 20 minutes per meal and chewing food thoroughly.

Related habits that increase air swallowing include chewing gum, drinking through straws, talking while eating, and smoking.

3. Fizzy drinks

Carbonated drinks introduce carbon dioxide directly into your digestive system. While some of this gas is released through burping, a portion travels further down the gut and can cause bloating and wind. This includes sparkling water, not just soft drinks — the carbonation itself is the issue.

4. Food intolerances

Food intolerances — particularly lactose intolerance and fructose malabsorption — are common causes of bloating. Unlike food allergies, which involve the immune system, intolerances are digestive issues where the body lacks sufficient enzymes to break down specific components of food.

Lactose intolerance affects an estimated 5-15% of people of Northern European descent, with higher rates in other populations. When undigested lactose reaches the colon, bacteria ferment it, producing gas and drawing water into the bowel — causing bloating, cramping, and diarrhoea.

If you're unsure whether you have a food allergy or intolerance, our article on food allergy vs intolerance explains the key differences and when to seek testing.

5. Constipation

When stool moves slowly through the colon, it gives bacteria more time to ferment residual food, producing additional gas. The physical presence of backed-up stool also leaves less room in the abdomen, making bloating feel worse. The NHS lists constipation as one of the most common causes of bloating.

6. Sudden increase in fibre

Fibre is essential for gut health, but increasing your intake too quickly can cause significant bloating. High-fibre foods like beans, lentils, and wholegrains are fermented by gut bacteria, and if your microbiome isn't adapted to a high-fibre diet, the result is excess gas. If you're experiencing bloating from bread, a rapid increase in wholegrain fibre could be the reason.

The solution isn't to avoid fibre — it's to increase gradually over 2-3 weeks and drink plenty of water.

7. Large portions

Simply eating too much at one sitting stretches the stomach and slows digestion, giving bacteria more time to ferment food. This is one of the most straightforward causes of post-meal bloating and the easiest to address.

High-FODMAP foods that commonly cause bloating

This table shows common trigger foods and which FODMAP group they belong to. Remember, not all of these will affect everyone — the point of the FODMAP approach is to identify your specific triggers.

Other factors that contribute to bloating

• Stress and anxiety — The gut-brain axis means stress can directly affect digestion, slowing gut motility and increasing sensitivity to gas. The NHS acknowledges this as a contributing factor in IBS-related bloating.
• Hormonal changes — Many women experience increased bloating before and during their period due to progesterone's effect on gut motility and water retention.
• Medications — Certain medications, including some painkillers, antidepressants, and iron supplements, can slow digestion and cause bloating.
• Small intestinal bacterial overgrowth (SIBO) — An overgrowth of bacteria in the small intestine can cause excessive gas production. This requires medical diagnosis and treatment.

Practical steps to reduce bloating

These are evidence-based strategies recommended by the NHS, NICE, and the British Dietetic Association:

1. Eat slowly and chew thoroughly — Aim for at least 20 minutes per meal. Put your fork down between bites. This reduces air swallowing and gives your brain time to register fullness.
2. Keep a food and symptom diary — Track what you eat and when bloating occurs. Patterns often emerge within 1-2 weeks. A bloating tracker can make this process simpler.
3. Consider a low-FODMAP trial — If bloating is frequent, a structured low-FODMAP elimination and reintroduction (ideally guided by a registered dietitian) can identify specific triggers. The Monash University FODMAP app is a reliable resource for food ratings.
4. Reduce fizzy drinks — Switch to still water, herbal teas, or non-carbonated drinks, particularly around mealtimes.
5. Stay active — Regular physical activity helps stimulate gut motility and reduce gas retention. Even a 15-20 minute walk after a meal can help.
6. Increase fibre gradually — If your diet is currently low in fibre, add high-fibre foods slowly over 2-3 weeks to give your gut bacteria time to adapt.
7. Address constipation — Ensure adequate water intake (6-8 glasses daily), include fibre-rich foods, and stay physically active. If constipation persists, see your GP.
8. Limit sugar-free products — Artificial sweeteners like sorbitol, mannitol, and xylitol (common in sugar-free sweets and gum) are known to cause bloating and gas.

The role of a food diary

Identifying your specific bloating triggers is far more useful than following generic advice. What bloats one person may be perfectly fine for another. A food and symptom diary is the simplest and most effective tool for making this personal.

For each meal, record:

• What you ate and drank (including quantities)
• The time you ate
• How quickly you ate
• Any symptoms that followed (bloating, gas, pain, changes to bowel habit)
• How long symptoms lasted
• Stress levels and sleep quality (these affect digestion too)

After 1-2 weeks, review the diary for patterns. You may find that bloating consistently follows specific foods, eating occasions (rushed lunches at work, for example), or times of the day. This information is also invaluable if you need to see a GP or dietitian — it gives them concrete data rather than vague descriptions.

For a more detailed look at common foods that cause bloating, see our dedicated guide.

Frequently asked questions

Why do I get bloated after every meal?

Bloating after every meal can be caused by eating too quickly, consuming high-FODMAP foods, an underlying food intolerance, or simply eating large portions. Constipation can also make post-meal bloating worse. If it happens consistently, keeping a food diary for 1-2 weeks is the best starting point. If symptoms persist, see your GP to rule out underlying conditions.

What foods are most likely to cause bloating?

The most common culprits are high-FODMAP foods: onions, garlic, wheat-based products, beans, lentils, apples, pears, milk, and artificial sweeteners. Fizzy drinks and cruciferous vegetables (broccoli, cabbage, Brussels sprouts) are also frequent triggers. However, triggers vary widely between individuals, which is why personal tracking is more useful than generic food lists.

How long does bloating after eating normally last?

Mild bloating typically resolves within 2-4 hours as food is digested and gas passes naturally. Bloating from high-FODMAP foods may last longer — up to 6-8 hours — as gut bacteria ferment undigested carbohydrates in the colon. If bloating lasts more than 24 hours or is accompanied by significant pain, see your GP.

Is bloating a sign of food intolerance?

Bloating is one of the most common symptoms of food intolerance, particularly lactose intolerance and fructose malabsorption. Unlike allergies (which involve the immune system), intolerances cause delayed digestive symptoms. If you suspect an intolerance, your GP can arrange testing, or you can read more in our guide to food allergy vs intolerance.

When should I see a GP about bloating?

See your GP if bloating is persistent (lasting most days for 3 weeks or more), getting progressively worse, or accompanied by unexplained weight loss, blood in your stool, changes in bowel habits, loss of appetite, or abdominal pain. These symptoms don't necessarily mean something serious, but they should always be checked professionally.

Related articles

• Why Does Bread Make Me Bloated?
• How to Track Food Intolerances
• Food Allergy vs Intolerance: What's the Difference?
• Bloating Tracker UK
• Foods That Cause Bloating
• FODMAP Tracker UK

Last reviewed and updated: 7 February 2026