Passing gas up to 25 times a day is considered normal, so “gassy” is relative. But if you’ve noticed a real uptick lately, something has likely changed in your diet, your daily habits, or the balance of bacteria in your gut. The good news: most causes are harmless and fixable once you identify them.
Where Gas Actually Comes From
Your body produces gas through two main routes. The first is swallowed air, which accounts for most of the gas in your stomach. You swallow a few milliliters of air with every bite of food or gulp of saliva, and most of it comes back up as a burp before it ever reaches your intestines.
The second source is far more productive: bacterial fermentation in your large intestine. When carbohydrates escape digestion in the small intestine, trillions of gut bacteria feast on them and produce hydrogen, carbon dioxide, and sometimes methane as byproducts. This is the primary driver of flatulence. The more undigested material that reaches your colon, the more gas your bacteria generate.
Dietary Changes Are the Most Common Trigger
If your gas ramped up after you changed what you eat, that’s almost certainly the explanation. Certain carbohydrates are poorly absorbed in the small intestine and become prime fuel for gas-producing bacteria. These are sometimes grouped under the acronym FODMAPs, which includes specific sugars found in a wide range of everyday foods:
- Beans and lentils: loaded with complex sugars that human enzymes can’t break down
- Dairy: milk, yogurt, and ice cream contain lactose, which many adults digest poorly
- Wheat-based products: bread, cereal, crackers
- Certain vegetables: onions, garlic, asparagus, artichokes
- Certain fruits: apples, pears, cherries, peaches
You don’t need to have a diagnosed intolerance for these foods to cause gas. Simply eating more of them than usual, like adding more fiber, switching to a plant-heavy diet, or snacking on more fruit, can dramatically increase fermentation in your colon. Even a positive change like eating more vegetables can temporarily make you gassier until your gut bacteria adjust.
Lactose Intolerance Can Develop in Adulthood
About 65 percent of the global population has a reduced ability to digest lactose after infancy. This isn’t an allergy; it’s a gradual decline in the enzyme that breaks down milk sugar. In people of East Asian descent, the rate is 70 to 100 percent. It’s also very common in people of West African, Arab, Greek, and Italian descent, while only about 5 percent of people with Northern European ancestry are affected.
What makes this tricky is that the decline can happen slowly over years. You might have handled dairy fine in your twenties and then start noticing bloating, gas, and cramping in your thirties or forties. The symptoms typically hit 30 minutes to 2 hours after consuming dairy. If your increased gas lines up with meals containing milk, cheese, or ice cream, this is worth investigating.
Everyday Habits That Increase Swallowed Air
Not all gas comes from fermentation. Swallowing excess air, a condition called aerophagia, pushes gas into your digestive tract that has to go somewhere. Common culprits include eating too fast, talking while eating, chewing gum, sucking on hard candy, drinking through straws, carbonated beverages, and smoking. If you’ve recently picked up any of these habits, or if stress has you eating faster than usual, that could explain the change.
Carbonated drinks deserve special mention because they deliver gas directly into your stomach. If you’ve swapped water for sparkling water or started drinking more soda, the math is straightforward.
Your Gut Bacteria May Have Shifted
Your intestinal microbiome is a complex ecosystem, and its composition determines how much gas you produce from any given meal. Dozens of bacterial species generate hydrogen and carbon dioxide during fermentation, while a separate group of organisms called methanogens convert some of that hydrogen into methane. The balance between these populations affects both the volume and the smell of your gas.
Several things can shift this balance: a course of antibiotics, a stomach bug, travel, prolonged stress, or a significant dietary change. After antibiotics in particular, some bacterial populations bounce back faster than others, which can temporarily increase gas production until the ecosystem stabilizes. If your gassiness started after an illness or a round of medication, a disrupted microbiome is a likely explanation.
Conditions Worth Knowing About
Most increased gas is dietary or behavioral. But persistent, uncomfortable gas alongside other symptoms can point to something that needs attention. Small intestinal bacterial overgrowth (SIBO) occurs when bacteria that normally live in the large intestine colonize the small intestine, where they ferment food earlier in the digestive process. The hallmark symptoms are bloating, diarrhea, and abdominal pain. A breath test can help with diagnosis.
Irritable bowel syndrome (IBS) is another possibility, especially if your gas comes with alternating constipation and diarrhea or cramping that improves after a bowel movement. Both SIBO and IBS respond well to dietary management, particularly a structured low-FODMAP approach.
Red flags that warrant a conversation with your doctor include sudden changes in your symptoms, unintended weight loss, blood in your stool, or persistent abdominal pain alongside the gas.
What You Can Do Right Now
Start by looking at what changed. A food diary for a week or two is the simplest diagnostic tool. Write down what you eat and when your gas is worst. Patterns tend to emerge quickly, especially around high-FODMAP foods and dairy.
If you suspect specific foods, try pulling them out for two to six weeks and see if symptoms improve. This is the basic principle behind a low-FODMAP elimination diet: remove the likely triggers, wait for relief, then reintroduce foods one at a time to identify your personal culprits. Most people notice improvement within the first two weeks.
Two types of over-the-counter products can help in the meantime. Enzyme supplements containing alpha-galactosidase (the active ingredient in products like Beano) break down the complex sugars in beans, lentils, and cruciferous vegetables before your gut bacteria can ferment them. You take them with the first bite of a triggering meal. The other option, simethicone (found in Gas-X), doesn’t prevent gas production but breaks up gas bubbles in your intestines so they’re easier to pass. It treats the discomfort rather than the cause.
Slowing down at meals makes a real difference too. Eating more slowly, putting your fork down between bites, and avoiding conversation while chewing all reduce the amount of air you swallow. If you chew gum regularly, cutting back for a week is an easy experiment.