Bloating is a feeling that your tummy is overly full or stretched. You may also have cramps, burping, diarrhoea, constipation, swelling and a lot of gas.
It happens when the organs of your digestive system are stretched, for example when liquid, gas or solids pool in part of your gut. It can also happen when the contents of your stomach move too slowly through the digestive system; when you have weak muscles in the wall of your tummy; or when your diaphragm muscle contracts instead of relaxing.
What causes bloating?
Bloating is usually caused by changes in your diet, for example if you have eaten a lot of rich food. One theory is that what you eat changes the type of bacteria you have in your gut, leading to bloating and gas.
Eating a lot of salty food and carbohydrates can make you feel bloated, as can swallowing air when you eat too fast or drink a lot of fizzy drinks.
Regular bloating can be caused by other problems, including:
When should I see my doctor?
Rarely, bloating can signify that something more serious is wrong. If your bloating doesn’t get better by following the steps above, you should see your doctor. Seek medical attention if you have bloating as well as:
- diarrhoea
- persistent or severe abdominal pain
- blood in your stools (poo)
- changes in the colour or frequency of your stools
- weight loss without trying to lose weight
- loss of appetite or feeling full quickly
CHECK YOUR SYMPTOMS — Use our Symptom Checker and find out if you need to seek medical help.
How is bloating treated?
Bloating will usually go away by itself if you adjust your diet for a while. Cut down on salty foods, carbohydrates and fizzy drinks. For some people, it can help to avoid foods that contain onion or garlic, wheat, rye, lactose products or stone fruit.
Bloating caused by constipation can be treated by eating more high-fibre foods, increasing the amount of water that you drink, and exercising regularly. Some people may need laxatives to treat constipation.
If you have a medical condition such as coeliac disease, you will need to follow a strict diet to prevent bloating and other symptoms. If you have IBS, following a high-fibre diet and the low FODMAP diet may help. This involves cutting out some dairy products, wheat and other grains, and some fruits and vegetables. Talk to a health professional such as your doctor or a dietitian before starting this diet to make sure it is right for you.
If you have a food intolerance, you may need to try an elimination diet to find out which food or foods are causing your problems. Your doctor or dietitian will advise you.
Some people find that probiotics containing lactobacillus and bifidobacterium can help with bloating by reducing the production of gas in the gut.
Can bloating be prevented?
To keep your digestive system working well, follow a healthy diet and eat at least 30g of fibre every day. Cut down on processed and fatty foods, and drink less alcohol. Drink plenty of water and take any medicines as directed by your doctor.
Don’t overeat, and try to eat more slowly. Eating regularly will help to prevent digestive problems.
Regular exercise is also important for your gut because it strengthens the muscles in your tummy and stimulates the digestive system to push food through. It also helps with stress, which affects the nerves in the digestive system and can slow down digestion.
Gas symptoms vary from person to person. Common symptoms of gas in the digestive tract include belching, bloating and distention, and passing gas. Having some gas symptoms is normal, especially during or after meals.
Gas symptoms may be a problem if they occur often, bother you, or affect your daily activities.
Belching
Belching, or burping, is a release of gas from your stomach through your mouth. People typically belch up to 30 times a day.3
Some people may feel they belch more often than normal. In some cases, people belch a lot because they swallow too much air and release the air before it enters the stomach.
Bloating and distention
Bloating is a feeling of fullness or swelling in your abdomen, or belly. If your abdomen becomes larger than usual, doctors call this distention. Only about half of people with bloating also have distention.4,5 Some people may also feel abdominal discomfort or pain when they have bloating or distention.
Passing gas
Studies suggest that people pass gas through the anus an average of 8 to 14 times a day.6 However, some people may pass gas more often. Experts consider passing gas up to 25 times a day to be normal.6,7
Excess gas in the digestive tract that leads to passing gas is called flatulence. The gas that passes is called flatus. People who have problems with flatulence may feel they pass too much gas or that the flatus has an unpleasant odor. The odor may be due to sulfur in the flatus.
When should I talk with a doctor about my gas symptoms?
You should talk with your doctor if
- gas symptoms bother you
- your symptoms change suddenly
- you have other symptoms—such as abdominal pain, constipation, diarrhea, or weight loss—along with gas symptoms
What causes gas?
Gas normally enters your digestive tract when you swallow air and when bacteria in your large intestine break down undigested carbohydrates. You may have more gas symptoms if you swallow more air or consume more of certain foods and drinks.
Swallowed air
Everyone swallows a small amount of air when eating and drinking. Swallowed air that doesn’t leave your stomach when you belch may move into your intestines and pass through your anus.
Swallowing more air may lead to more gas and gas symptoms. You swallow more air when you
- chew gum or suck on hard candy
- drink carbonated, or fizzy, drinks
- eat or drink too fast
- smoke
- wear loose-fitting dentures
Bacteria in your large intestine
Your large intestine contains a large number of bacteria and some fungi and viruses that make up the gut microbiome—the microbes in your digestive tract that help with digestion. Bacteria in the large intestine help break down carbohydrates and create gas in the process.
Certain foods and drinks contain types of carbohydrates—sugars, starches, and fiber—that your stomach and small intestine don’t fully digest. Undigested carbohydrates will pass to your large intestine, where bacteria break them down and create gas. You may have more gas symptoms if you consume more carbohydrates that your stomach and small intestine don’t fully digest.
What health conditions can cause problems with gas symptoms?
Some health conditions can cause you to have more gas than usual or have more gas symptoms.
IBS and other functional GI disorders
Functional gastrointestinal (GI) disorders such as irritable bowel syndrome (IBS), functional abdominal bloating and distention, functional constipation, and functional dyspepsia may cause problems with gas symptoms.
Functional GI disorders are related to problems with how your brain and your gut work together. These problems can cause you to feel more bloating or abdominal pain or can affect how gas moves through your intestines.
Problems digesting carbohydrates
People who have problems digesting certain carbohydrates may experience digestive symptoms—such as bloating, abdominal pain, and diarrhea—after they consume certain foods or drinks. Problems digesting carbohydrates include
- lactose intolerance, in which people have digestive symptoms after consuming foods or drinks that contain lactose
- dietary fructose intolerance, in which people have digestive symptoms after consuming foods or drinks that contain fructose
Small intestinal bacterial overgrowth
Small intestinal bacterial overgrowth is an increase in the number of bacteria or a change in the type of bacteria in your small intestine. These bacteria can produce extra gas and may also cause diarrhea and weight loss. Small intestinal bacterial overgrowth is most often a complication of other health conditions.
Other digestive diseases and conditions
A number of other digestive diseases and conditions may lead to more gas or gas symptoms, including
- celiac disease
- constipation
- gastroesophageal reflux disease
- gastroparesis
- intestinal pseudo-obstruction
- obstruction or blockage of the digestive tract, which may be caused by conditions such as colorectal, ovarian, or stomach cancer
References
[3] Zad M, Bredenoord AJ. Chronic burping and belching. Current Treatment Options in Gastroenterology. Published online January 23, 2020. doi: 10.1007/s11938-020-00276-0
[4] Lacy BE, Cangemi D, Vazquez-Roque M. Management of chronic abdominal distension and bloating. Clinical Gastroenterology and Hepatology. 2021;19(2):219–231.e1. doi: 10.1016/j.cgh.2020.03.056
[5] Cotter TG, Gurney M, Loftus CG. Gas and bloating-controlling emissions: a case-based review for the primary care provider. Mayo Clinic Proceedings. 2016;91(8):1105–1113. doi: 10.1016/j.mayocp.2016.04.017
[6] Rao SSC, Lee YY. Chapter 40: Approach to the patient with gas and bloating. In: Podolsky DK, Camilleri M, Fitz G, et al, eds. Yamada’s Textbook of Gastroenterology. 6th ed. John Wiley & Sons, Ltd; 2016:723–734.