Passing gas anywhere from 10 to 25 times a day is completely normal, producing roughly 500 to 1,500 ml of gas in 24 hours. If you feel like you’re farting constantly, you’re likely on the higher end of that range or just more aware of it than usual. The good news is that the cause is almost always dietary or behavioral, and a few targeted changes can make a noticeable difference within weeks.
What Creates Gas in Your Body
Gas comes from two sources: swallowed air and bacterial fermentation in your large intestine. Most of the air you swallow gets burped back up, but some travels through your digestive tract and exits the other end. The larger contributor to flatulence is fermentation. When your gut bacteria break down carbohydrates that weren’t fully digested in the small intestine, they produce hydrogen, carbon dioxide, and sometimes methane. The more undigested material that reaches your colon, the more gas you produce.
When researchers put healthy volunteers on a fiber-free liquid diet for 48 hours, their total gas output dropped by roughly 70%, from a median of 705 ml to just 214 ml per day. That tells you how much of your daily gas is directly tied to the food you eat.
The Foods Most Likely to Blame
A group of short-chain carbohydrates called FODMAPs are the biggest gas producers for most people. These are sugars and fibers found in everyday foods that your small intestine absorbs poorly, leaving them for your colon bacteria to feast on. Common high-FODMAP foods include beans, lentils, onions, garlic, wheat, apples, pears, cauliflower, and dairy products containing lactose. In controlled studies, a high-FODMAP diet produced roughly four times more hydrogen gas over the course of a day compared to a low-FODMAP diet, even in healthy people without any digestive conditions.
If you recently increased your fiber intake, that alone could explain the problem. Adding beans, whole grains, or vegetables to a diet that was previously low in fiber overwhelms your gut bacteria temporarily. The good news: your microbiome adjusts. Studies on people adding beans to their diet found that gas production returned to normal levels within three to four weeks. The key is increasing fiber gradually rather than all at once.
Sugar Alcohols Are a Hidden Trigger
Sugar-free gum, mints, protein bars, and “keto-friendly” snacks often contain sugar alcohols like sorbitol, xylitol, and maltitol. These are poorly absorbed and ferment in the colon just like FODMAPs. Sorbitol can cause digestive upset at doses as low as 15 to 30 grams. Maltitol starts producing noticeable gas and gurgling at around 40 grams, and 45 grams caused watery diarrhea in 85% of study participants. Check ingredient labels for anything ending in “-ol” or “-itol.” A couple of sugar-free candies probably won’t bother you, but chewing through a pack of sugar-free gum in an afternoon easily pushes you past the threshold.
Habits That Make You Swallow Air
Swallowed air, known as aerophagia, adds gas to your system before food even reaches your colon. The most common culprits are eating too fast, talking while you eat, chewing gum, sucking on hard candy, drinking through straws, and drinking carbonated beverages. Smoking also increases the amount of air you swallow. These are easy to overlook because each one seems minor on its own, but stacking several of these habits throughout the day adds up. Slowing down at meals, taking sips from a glass instead of a straw, and cutting back on sparkling water can reduce this type of gas noticeably.
Food Intolerances You Might Not Know About
Lactose intolerance is one of the most common reasons for persistent gas, and many people develop it gradually in adulthood without realizing it. When your body doesn’t produce enough of the enzyme that breaks down lactose (the sugar in milk), it passes undigested into the colon, where bacteria ferment it into gas. Symptoms typically start within a few hours of eating dairy and include bloating, cramping, gas, and sometimes diarrhea.
A simple way to test this is to eliminate dairy for a week and see if your symptoms improve. You can also try lactose-free milk or take a lactase enzyme supplement before eating dairy. Gluten sensitivity and fructose malabsorption can cause similar patterns, though they’re less common than lactose intolerance.
When Gas Signals Something Deeper
In most cases, excessive gas is a nuisance, not a medical problem. But certain patterns suggest something more is going on. Small intestinal bacterial overgrowth (SIBO) occurs when bacteria that normally live in the large intestine colonize the small intestine instead, fermenting food too early in the digestive process. SIBO causes persistent bloating, gas, abdominal pain, diarrhea, and sometimes unintentional weight loss or malnutrition. It’s more common in people who’ve had abdominal surgery or who have conditions that slow gut motility.
Irritable bowel syndrome (IBS) is another possibility. People with IBS produce more hydrogen gas on the same diet compared to people without IBS, and they experience more discomfort from the same amount of gas. Their gut is essentially more sensitive to distension. A low-FODMAP diet, guided by a dietitian, is one of the most effective approaches for IBS-related gas.
See a doctor if your gas comes with bloody stools, unexplained weight loss, persistent diarrhea or constipation, ongoing nausea, or prolonged abdominal pain. These can point to conditions like celiac disease, inflammatory bowel disease, or other issues that need proper evaluation.
What Actually Helps Reduce Gas
Start by identifying your triggers. A food diary where you track what you eat and when your symptoms flare can reveal patterns within a week or two. Once you have suspects, try eliminating one category at a time (dairy, high-FODMAP vegetables, sugar alcohols) for a few days and note what changes.
For gas caused by beans and high-fiber vegetables, an enzyme supplement sold under the brand name Beano can help. It works by breaking down the specific carbohydrates that your body can’t digest before they reach your colon bacteria. In clinical trials, it significantly reduced both bloating and flatulence compared to placebo. You take it with the first bite of a problem food.
Simethicone, the active ingredient in Gas-X, works differently. It doesn’t prevent gas from forming. Instead, it combines small gas bubbles into larger ones that are easier to pass. The clinical evidence for simethicone actually reducing total gas is weak, but some people find it helps with the discomfort of feeling bloated.
Probiotics get a lot of attention, but the evidence is mixed. A systematic review found that most probiotics tested did not significantly reduce flatulence in people with IBS. A few specific strains showed some benefit in people without IBS: one strain of Bifidobacterium helped women with mild digestive symptoms, and Lactobacillus reuteri reduced gas in people with lactose intolerance. Probiotics aren’t a guaranteed fix, but they’re unlikely to make things worse.
The most reliable approach is dietary. Reduce your intake of the highest-gas foods, increase fiber slowly if you’re adding it, cut back on sugar alcohols, and slow down when you eat. Most people who make these changes notice a meaningful difference within two to four weeks as their gut bacteria adapt to the new routine.