Passing gas 13 to 21 times a day is completely normal for adults. If you’re noticing more than that, or your gas feels unusually frequent compared to your baseline, the cause almost always comes down to what you’re eating, how you’re eating it, or the specific mix of bacteria living in your gut. In most cases, the fix is straightforward once you identify the trigger.
How Your Body Makes Gas
Gas comes from two sources: swallowed air and bacterial fermentation. Every time you eat, drink, or swallow saliva, small amounts of air travel into your digestive tract. Most of it gets burped back up, but some continues down into the intestines and eventually comes out the other end.
The bigger contributor to flatulence is fermentation in your large intestine. Your body can’t fully break down certain carbohydrates, so they pass through your stomach and small intestine relatively intact. When they reach your colon, trillions of bacteria go to work on them, producing hydrogen, carbon dioxide, and sometimes methane as byproducts. The volume of gas you produce depends on two things: how much undigested material reaches your colon and which types of bacteria are doing the fermenting. Both vary significantly from person to person, which is why two people can eat the same meal and have very different results.
Foods That Produce the Most Gas
A group of short-chain carbohydrates known as FODMAPs are among the most common gas triggers. These sugars aren’t completely digested or absorbed in the small intestine. Instead, they move slowly through the gut, drawing water in as they go. Once they reach the large intestine, bacteria ferment them rapidly, producing a burst of gas.
The main categories include:
- Fructans and GOS: found in wheat, onions, garlic, and legumes like beans and lentils
- Lactose: the sugar in milk, soft cheeses, yogurt, and ice cream
- Excess fructose: found in honey, apples, pears, and high-fructose corn syrup
- Sugar alcohols (sorbitol and mannitol): common in sugar-free gum, mints, and some stone fruits
Fiber is another major player. High-fiber foods like beans, broccoli, cabbage, and whole grains are genuinely good for your digestive health, but they deliver a lot of undigested material to your colon at once. If you’ve recently increased your fiber intake, that alone could explain a spike in gas. Your gut bacteria need a few weeks to adjust to a higher-fiber diet, so adding fiber gradually and drinking plenty of water can make a real difference.
Habits That Make You Swallow Extra Air
Sometimes the issue isn’t fermentation at all. You may be swallowing more air than you realize, a pattern called aerophagia. Common culprits include eating too fast, talking while you eat, chewing gum, sucking on hard candy, drinking through a straw, and sipping carbonated beverages. Smoking also increases the amount of air you take in. Each of these habits is easy to overlook because no single one feels significant, but they can add up over the course of a day. If your gas is mostly odorless, swallowed air is a likely contributor, since the smellier component tends to come from bacterial fermentation of sulfur-containing foods.
Food Intolerances and Enzyme Deficiencies
If gas consistently hits within a few hours of eating dairy, lactose intolerance is a strong possibility. People with this condition don’t produce enough of the enzyme that breaks down lactose, so the sugar passes intact into the colon where bacteria ferment it aggressively. The pattern is usually predictable: dairy in, gas and bloating a couple of hours later. Lactose intolerance is extremely common globally and can develop at any age, even if dairy never bothered you before.
Fructose malabsorption works similarly. Your small intestine has a limited capacity to absorb fructose, and some people hit that ceiling faster than others. Large servings of fruit, fruit juice, or foods sweetened with high-fructose corn syrup can overwhelm that capacity and send unabsorbed fructose straight to the colon for fermentation. Keeping a simple food diary for a week or two can help you spot whether a specific food group consistently triggers your symptoms.
When Your Gut Bacteria Are Part of the Problem
Your individual microbiome plays a surprisingly large role. Two people eating identical meals can produce very different amounts of gas simply because their bacterial populations differ. Some people harbor methane-producing bacteria that others lack entirely, changing both the volume and composition of their gas.
In some cases, bacteria that normally belong in the large intestine migrate upward and colonize the small intestine, a condition called small intestinal bacterial overgrowth (SIBO). When this happens, food gets fermented much earlier in the digestive process than it should, producing excess gas along with bloating, nausea, diarrhea or constipation, and sometimes unintentional weight loss. SIBO can be clinically verified with a breath test, and it’s one of the first things a doctor will check if your gas is persistent and accompanied by other digestive symptoms.
There is also preliminary evidence that certain probiotics can reduce the volume of gas your gut produces and ease related digestive symptoms, though results vary by person and strain.
Practical Ways to Reduce Gas
Start with the simplest changes first. Slow down when you eat, put your fork down between bites, and avoid talking with food in your mouth. Cut back on carbonated drinks and gum for a week and see if that alone makes a noticeable difference.
If swallowed air isn’t the issue, look at your diet. Try reducing one high-FODMAP food group at a time for a few days to see which triggers the most gas. Beans and lentils are classic offenders, but onions, garlic, and wheat catch a lot of people off guard. If you suspect dairy, try switching to lactose-free versions for a week. The pattern usually becomes obvious quickly.
For fiber specifically, the key is gradual introduction. Adding too much too fast is one of the most common reasons people suddenly notice a dramatic increase in gas. Increase your intake slowly over a few weeks and pair it with extra water, which helps fiber move through your system more smoothly.
Over-the-counter options can help in specific situations. Products containing simethicone work by breaking up gas bubbles that have already formed in your digestive tract, which can relieve the uncomfortable pressure and bloating. They won’t reduce the amount of gas your bacteria produce, but they can make what’s there easier to pass. Enzyme supplements designed to break down lactose or the complex sugars in beans can prevent gas from forming in the first place if you take them with the trigger food.
Signs That Something More Serious Is Going On
Excessive gas by itself is rarely a sign of a dangerous condition. But if it comes alongside bloody stools, unexplained weight loss, persistent diarrhea or constipation, ongoing nausea or vomiting, or a noticeable change in your bowel habits, those combinations warrant medical attention. Prolonged abdominal pain that doesn’t resolve is another signal worth taking seriously. In most cases, testing will reveal something manageable like SIBO, lactose intolerance, or irritable bowel syndrome, all of which respond well to targeted treatment.