New research suggests adults fart far more often than previously thought, with the average healthy person passing gas around 32 times a day — more than double the long‑accepted estimate of five to 15 daily emissions.
Scientists at the University of Maryland reached the figure using a novel device they call “Smart Underwear,” a wearable garment fitted with electrochemical sensors that continuously monitor intestinal gas production. The technology marks a significant leap forward from older studies, which relied on self‑reporting or invasive rectal tubes and were prone to memory errors, missed events during sleep and discomfort. The result is the most objective data yet on a bodily function that, despite its universality, has been surprisingly poorly understood.
The research, part of a larger project named the Human Flatus Atlas, recorded a wide variation between individuals. Some participants produced as few as four emissions a day, while others reached 59. In ongoing studies, researchers have even documented people farting up to 175 times daily on the same diet. Brantley Hall, assistant professor in the Department of Cell Biology and Molecular Genetics at the University of Maryland, said: “We don’t actually know what normal flatus production looks like. Without that baseline, it’s hard to know when someone’s gas production is truly excessive.”
The science behind the gas
The production and expulsion of wind is a normal part of digestion, driven primarily by bacteria in the gut breaking down food through fermentation. This process creates gases including hydrogen, methane and carbon dioxide. The amount of gas produced depends heavily on diet, the composition of an individual’s gut microbiome and general health.
Foods high in fibre are common culprits because they take longer to break down, giving gut bacteria more time to ferment them. Whole grains, beans, lentils and vegetables such as broccoli, cauliflower and cabbage are particularly well known for encouraging flatulence. The distinctive smell comes from sulphur‑containing compounds released when certain foods are broken down — cruciferous vegetables and alliums such as garlic and onions are major contributors. As the researchers note, that egg‑mayo sandwich from lunch is likely to make its presence felt later in the day.
Some gas also enters the body when we eat, drink, talk or swallow saliva. That air usually exits the same way it arrived, through burping rather than farting, but not always. The researchers stress that the function is not a bad sign — in many cases, it simply means gut bacteria are doing exactly what they are supposed to do as they break down complex carbohydrates and fibre. Ironically, many of the foods linked to flatulence are among the healthiest.
Age, health and when to worry
Age can affect how frequently we fart, although not always in the dramatic way people fear. Metabolism and digestion naturally slow down as we get older. Food moves more slowly through the digestive tract, which can allow gases to build up in the bowel and linger for longer. Changes to stomach acid production may also make certain foods harder to digest than they once were, meaning someone who happily demolished spicy takeaways in their twenties may suddenly find themselves battling digestive revenge after an innocent dinner later in life.
Muscle tone plays a role too. The muscles around the digestive tract and anus naturally weaken slightly with age, which may make it harder to hold in gas or prevent it escaping unexpectedly. Some medications can contribute, alongside conditions such as irritable bowel syndrome, coeliac disease, inflammatory bowel disease, lactose intolerance and small intestinal bacterial overgrowth (SIBO).
While increased flatulence is often normal, experts say sudden changes can sometimes point to underlying problems. Persistent bloating, pain, diarrhoea, unexplained weight loss or major appetite changes alongside increased gas can occasionally signal digestive conditions including coeliac disease, inflammatory bowel disease or SIBO. The Human Flatus Atlas project, which is recruiting participants across the US, aims to build a clearer picture of how much gas healthy people produce throughout everyday life. By analysing diet and gut microbiome composition alongside the Smart Underwear data, researchers hope to better understand digestive disorders and eventually help doctors identify when gas is truly excessive.