We’ve all been there: feeling like your stomach is about to pop after a meal. Generally, that’s a bad thing, and overeating is a major health problem in many parts of the world. But sometimes, there’s another problem: bloating. Bloating occurs when your gastrointestinal tract is filled with excess gas, literally inflating your stomach, which feels full and tight. It can all be very uncomfortable and painful, and burping and belching do little to help.

Although it might look like bloating is caused by eating too much, it’s actually more of a question of what food you eat. A new study from the Johns Hopkins Bloomberg School of Public Health found that individuals who ate a high-salt diet reported more gastrointestinal bloating. The researchers also found evidence that high-fiber diets also contribute to bloating.

“Bloating is one of the leading gastrointestinal complaints in the U.S. and can be exacerbated in some people by a high-fiber diet; our results suggest that they might be able to reduce that bloating, without compromising on healthy fiber, by lowering their sodium intake,” says study senior author Noel Mueller, an assistant professor in the Department of Epidemiology at the Bloomberg School.

Up to a third of U.S. adults experience stomach bloating on a regular basis and among patients with irritable bowel syndrome, that incidence shoots to over 90%. There are many different reasons that may cause bloating, including constipation, hormonal imbalances, excess gas due to digestion, and underlying health conditions, such as an infection, food sensitivity, irritable bowel syndrome, and even stress.

Diet is also a major factor that can lead to a bloating gut. Recently, researchers resurrected data from a two-decade-old study, known as the DASH-Sodium trial. The study was conducted between 1998 and 1999 at four clinical centers with 412 participants with high blood pressure. The participants tested the DASH diet, a then-novel diet high in fiber and low in fat, involving eating lots of fruits, nuts, and vegetables.

Although the trial was chiefly concerned with how a high-fiber diet might reduce high blood pressure, the diet was tested at three levels of sodium, which piqued Muller’s interest.

This data was used by Mueller and colleagues to investigate the effect of dietary sodium on bloating. The researchers found that the high-fiber DASH diet increased the risk of bloating by 41%, compared to the low-fiber control diet, with men being affected more than women. That was surprising since the conventional advice offered to reduce bloating is to eat more fiber.

But the study also found that consuming too much salt contributed significantly to the risk of bloating, with the high-sodium version of DASH increasing the overall risk of bloating by 27% — meaning on top of the additional risk of bloating caused by consuming lots of fiber — compared to the low-sodium diet.

It’s not clear how sodium leads to bloating, although scientists suspect sodium’s water retention properties may be to blame. Sodium intake may also alter the gut microbiome, thereby modifying bacterial sulfide production. Currently, Muller and team are looking into how protein, carbs, and fat affect bloating.

Occasional bloating is not uncommon and usually resolves by itself. But if you face constant bloating, doctors advise increasing exercise, limiting highly processed foods, increasing fluid intake while avoiding carbonated beverages, and having smaller meals.

The findings appeared in The American Journal of Gastroenterology.