Bloating is a feeling of fullness, pressure or tightness in the belly. Sometimes the belly also looks bigger, which doctors call distention. Gas, belching and passing gas are normal, especially during and after meals. When bloating is uncomfortable most days, makes your clothes feel tight by evening, or changes how you eat, it is worth looking into. Dr. Pimienta helps adults across Los Angeles County understand what is behind their bloating and what will actually help.
What causes bloating and gas?
Most bloating comes from one or more of these everyday causes:
- Swallowed air. Eating or drinking fast, chewing gum, sucking on hard candy, drinking through a straw, carbonated drinks, smoking and loose dentures all add air to the stomach. Much of it comes back up as belching.
- Foods that ferment. Some carbohydrates are not fully absorbed in the small intestine. Bacteria in the colon ferment them and make gas. These are often called FODMAPs and include beans, onions, garlic, wheat, some fruits such as apples and pears, milk sugar (lactose) and sugar-free sweeteners such as sorbitol.
- Lactose intolerance. Trouble digesting milk sugar causes gas, bloating and loose stools after dairy.
- Constipation. Stool that sits in the colon keeps fermenting and makes bloating worse. Treating constipation often eases bloating.
- Irritable bowel syndrome (IBS). In IBS the gut is more sensitive, so a normal amount of gas can feel like a lot.
- Small intestinal bacterial overgrowth (SIBO). In some people, too many bacteria grow in the small intestine, causing bloating, gas and diarrhea. It is more likely after some bowel surgeries or with conditions that slow the gut.
- Celiac disease. An immune reaction to gluten can cause bloating, diarrhea, weight loss and low iron.
- Medicines and supplements. Opioids, some diabetes medicines, fiber supplements started too fast, and GLP-1 medicines for diabetes and weight loss, which slow the stomach (see our article on GLP-1 medicines and your digestion).
- Hormone changes, such as before a menstrual period.
When does bloating need a check?
Bloating on its own is rarely a sign of something serious. See a doctor if bloating comes with any of these:
- Weight loss you cannot explain
- Vomiting, or feeling full after only a few bites
- Blood in your stool, or black stools
- Anemia (a low blood count) or low iron
- A belly that keeps getting bigger, or swelling that does not go down overnight
- Fever, diarrhea that does not stop, or a lasting change in bowel habits
- A family history of colon cancer, ovarian cancer, celiac disease or IBD
Women over 50: new bloating that persists, happens most days, and is a change from your normal should be checked by your doctor. Bloating like this is usually caused by something benign, but it can rarely be an early sign of ovarian cancer, so your doctor or gynecologist may recommend a pelvic exam or an ultrasound.
Call 911 or go to the nearest emergency room if bloating comes with severe or worsening belly pain, a hard or swollen belly with vomiting and being unable to pass gas or stool, a high fever with belly pain, or vomiting blood.
How can a food diary help?
A simple two-week diary often shows a pattern that is hard to see day to day. Bring it to your visit.
Write down what you eat and drink
Every meal, snack and drink, including gum, sodas and sugar-free products, with the time.
Rate your bloating
Note when it starts and how strong it is, from 0 to 10. Note if it is worse in the evening.
Track your bowel movements
How often you go and what the stool is like.
Note anything else
Medicines, stress, sleep, exercise and, for women, where you are in your menstrual cycle.
How does Dr. Pimienta evaluate bloating?
He starts by listening: when the bloating happens, how it relates to meals and bowel movements, what you eat, which medicines you take, and whether there are any warning signs. A physical exam follows. Many people need no tests at all. When tests will help, they are chosen to fit:
- Blood tests, such as a blood count and a celiac disease test.
- Stool tests when diarrhea is part of the picture.
- Imaging, such as an ultrasound or a CT scan, when the exam or symptoms call for it.
- Other tests that may be arranged, such as breath tests for lactose intolerance or bacterial overgrowth.
- Upper endoscopy (EGD) or colonoscopy when there are warning signs, when celiac disease needs to be confirmed, or when you are due for colorectal cancer screening.
What helps bloating and gas?
The best plan targets the cause. These steps help many people:
- Slow down at meals. Eat smaller portions, chew well, and skip gum, straws and fizzy drinks.
- Treat constipation if you have it. This alone often helps.
- Try lactose-free dairy for two weeks if symptoms follow milk products.
- Go easy on sugar-free products made with sorbitol, mannitol or xylitol.
- Add fiber slowly, and choose soluble fiber such as psyllium, which tends to cause less gas.
- Walk after meals. Gentle movement helps gas move through.
- Consider a low-FODMAP diet with a dietitian if bloating comes with IBS. It is a short-term elimination followed by adding foods back to find your own triggers.
Depending on the cause, medicines may help as well, such as peppermint oil or antispasmodics for IBS, treatment for constipation, a short course of antibiotics when bacterial overgrowth is confirmed, or adjusting a medicine that slows the gut. Your plan depends on your health. You and Dr. Pimienta decide together what fits you, and follow up to see what is working.
Questions patients ask
How much gas is normal?
More than most people think. Studies suggest people pass gas about 8 to 14 times a day on average, and up to 25 times can be normal. Belching after meals is normal too.
Why is my belly flat in the morning and bloated by evening?
This is very common. Food and gas build up in the gut over the day, so bloating often peaks in the evening and settles overnight. This pattern often points to diet, swallowed air, constipation or IBS rather than something serious.
Do over-the-counter gas pills work?
Simethicone helps some people with gas pain, though the evidence is limited. Lactase tablets help if lactose is the cause. Activated charcoal and many supplements have little proof behind them.
Should I be tested for SIBO?
Not everyone with bloating needs it. Testing makes the most sense when your history suggests bacterial overgrowth, for example after certain bowel surgeries. Dr. Pimienta will talk with you about whether it would change your care.
Can my weight-loss medicine cause bloating?
Yes. GLP-1 medicines slow how fast the stomach empties, which can cause fullness, bloating, burping and constipation, especially when the dose goes up. Smaller meals often help. Talk with your prescriber before changing your dose.