Healthy adults pass gas at least 14 times a day, so some flatulence is completely normal. But if you’re dealing with more than that, or the volume and smell are becoming a problem, there are practical ways to cut it down. Most excess gas comes from two sources: air you swallow and food your gut bacteria ferment. Targeting both makes a noticeable difference.
Where the Gas Actually Comes From
Your intestinal gas is a mix of swallowed air and gases produced by bacteria in your large intestine. Swallowed air mostly contains nitrogen and oxygen, and it tends to come back up as burps. The gas that exits the other end is primarily hydrogen and methane, produced when bacteria in your colon break down carbohydrates your small intestine couldn’t absorb. The more undigested material that reaches your colon, the more gas your bacteria produce.
This is why certain foods are so much worse than others. Beans, lentils, chickpeas, and other legumes are packed with a type of sugar called raffinose that humans simply lack the enzyme to break down. It passes through your stomach and small intestine untouched, then arrives in your colon where bacteria feast on it and release gas as a byproduct. The same process happens with other poorly absorbed carbohydrates found in onions, garlic, wheat, certain fruits, and dairy (if you’re lactose intolerant).
Foods That Cause the Most Gas
The biggest gas producers share a common trait: they contain short-chain carbohydrates that ferment rapidly in the colon. These are sometimes grouped under the term FODMAPs. In controlled studies, people eating a high-FODMAP diet produced roughly four times more hydrogen gas over the course of a day compared to a low-FODMAP diet. The difference is dramatic and measurable.
The most common culprits include:
- Legumes: beans, lentils, chickpeas, soybeans
- Cruciferous vegetables: broccoli, cabbage, Brussels sprouts, cauliflower
- Alliums: onions, garlic, leeks
- Dairy: milk, soft cheeses, ice cream (especially if lactose intolerant)
- Certain fruits: apples, pears, watermelon, stone fruits
- Sugar alcohols: sorbitol, mannitol, xylitol (found in sugar-free gum and candy)
- Wheat and rye in large quantities
You don’t necessarily need to eliminate all of these. Most people have a few specific triggers rather than a sensitivity to the entire list. Keeping a simple food diary for a week or two, noting what you eat and when you feel gassy, can help you identify your personal offenders quickly.
How to Prepare Gassy Foods So They’re Less Gassy
If beans and lentils are a staple in your diet, preparation methods can significantly reduce their gas-producing potential. Soaking dried beans overnight and discarding the soaking water removes a portion of the raffinose before cooking. Cooking itself breaks down more. Fermentation (as in tempeh or miso) and sprouting also reduce these sugars. Research on food processing shows that soaking, germination, fermentation, and cooking all lower the concentration of the specific sugars responsible for gas production.
Canned beans, which have been soaked and cooked during processing, tend to cause less gas than beans you cook from dry without soaking. Rinsing canned beans before eating them helps further.
Stop Swallowing So Much Air
A surprising amount of intestinal gas is simply air you swallowed without realizing it. The most common causes are eating too fast, talking while eating, chewing gum, sucking on hard candy, drinking through straws, consuming carbonated beverages, and smoking. Each of these either forces extra air into your stomach or introduces gas directly.
Slowing down at meals is one of the simplest and most effective changes you can make. When you eat quickly, you gulp air with every bite. Chewing thoroughly and putting your fork down between bites gives you time to swallow food without pulling in excess air. If you’re a regular gum chewer or a daily soda drinker, cutting back on either one can make a noticeable difference within days.
Increase Fiber Gradually
Fiber is one of the trickiest areas because it’s genuinely good for your digestive health, but adding too much too fast is one of the fastest ways to become uncomfortably gassy. Soluble fibers that ferment easily, like inulin, fructooligosaccharides, and resistant starch, are the biggest gas producers. Insoluble fibers like wheat bran and cellulose ferment poorly and tend to cause less gas.
If you’re increasing your fiber intake, the recommended approach is to add no more than 3 to 4 grams per day during the first week, then continue increasing slowly. Drinking at least 2 liters of water daily alongside the added fiber also helps. Most of the bloating and gas that people blame on “eating healthy” is really just the result of ramping up too quickly. Your gut bacteria need time to adjust to a new fuel source, and the gas production tends to settle down after a few weeks of consistent intake.
Supplements That Can Help
If you want to eat gas-producing foods without the consequences, enzyme supplements taken just before a meal can reduce fermentation. The most studied option is alpha-galactosidase, sold under brand names like Beano. It works by breaking down raffinose and similar sugars in your stomach and small intestine before they reach the bacteria in your colon. Clinical research shows that a sufficient dose produces a significant reduction in both hydrogen gas production and flatulence severity.
For lactose intolerance, lactase enzyme tablets work on the same principle, breaking down milk sugar before it reaches your colon.
Simethicone (the active ingredient in Gas-X) works differently. It doesn’t reduce how much gas your body produces. Instead, it acts as a surfactant that merges small gas bubbles into larger ones, making them easier to pass as a belch or flatulence. It can relieve the uncomfortable feeling of trapped gas, but it won’t reduce the total amount your body makes.
Move After You Eat
A short walk after eating helps gas move through your digestive tract faster. Light movement stimulates the muscles that push food and gas through your intestines, reducing the bloating and pressure that comes from gas sitting in one place too long. You don’t need an intense workout. Ten to fifteen minutes of casual walking after a meal is enough to keep things moving and prevent gas from building up uncomfortably.
When Gas Signals Something More
If you’re consistently producing significantly more gas than normal despite dietary changes, there may be an underlying cause worth investigating. Small intestinal bacterial overgrowth, or SIBO, occurs when bacteria that normally live in the large intestine colonize the small intestine, where they ferment food much earlier in the digestive process. This leads to excessive gas, bloating, and sometimes diarrhea or cramping. SIBO is typically diagnosed through a breath test that measures hydrogen and methane in your exhaled breath after drinking a sugar solution. An increase of 20 parts per million in hydrogen within 90 minutes suggests bacterial overgrowth.
Lactose intolerance, celiac disease, and other malabsorption conditions can also produce chronic excess gas because they allow nutrients to pass undigested into the colon. If your gas is accompanied by persistent changes in bowel habits, unexplained weight loss, or abdominal pain, those are signs that something beyond diet is going on.