We expect to feel our best when we’re on holiday, finally away from our laptop screens and the stresses of everyday life. But more often than not, our feel-good trips are scuppered by feeling a bit off. Not only is it common to get sick on holiday, but often we feel bloated before we’ve even landed.

If you’ve ever felt your belly stat to bloat when you are on a plane, you’ll be relieved to know that it’s a fairly common issue. In fact, it even has a name: mile high IBS. The question is: what causes that sky-high gas production, and is there anything we can do to stop it from happening?

Well, feeling gassy all comes down to atmospheric pressure changes that occur as the plane ascends. According to some scientific papers, most healthy people are able to comfortably hold up to 400ml of gas in the stomach and intestines (gas exists as a by-product of bacteria functioning in the gut, swallowing air when we eat and other gas exchanges in blood and organs). But the pressure at high altitudes makes the trapped air in your gut expand, taking up more room and leading to bloating and pain. 

“Even a small amount of gas in your gut at ground level expands when in the sky, putting extra strain on your gut,” explains Dr Megan Rossi, aka The Gut Health Doctor, in an Instagram reel. She compares it to how vacuum sealed food packets puff up when on a plane – the air inside the pack expands.

“This will happen to everyone, but those who suffer from IBS or have a more sensitive gut may experience extra pressure, [leading to more] bloating and pain,” Dr Rossi adds.

“If you do struggle with this, then cutting down on higher-FODMAP foods 24-48 hours before flying can really help,” writes Dr Rossi. 

FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols – complicated words to describe a type of short-chain carbohydrates. These foods are perfectly healthy in normal circumstances, including things like onion, garlic, apples, chickpeas and wheat-based products.

However, these are fermented foods that produce a lot of gas when they are digested so are best to avoid before flights. She suggests swapping high FODMAP fruits for less irritating berries and chickpeas and legumes for less fibrous protein sources such as eggs or tofu.

“Make sure you do reintroduce [these foods] once landed, as most FODMAPs are prebiotic fibre,” says Dr Rossi. 

Keeping hydrated is also crucial for good digestion when flying. Plane cabins are much drier than the atmosphere on land – at cruise altitudes relative humidity is maintained at 10–20% while London’s average humidity is 73%. That can cause dehydration which isn’t only bad for your skin, but can also cause constipation and bloating as the gut needs water to keep stools loose. 

In a 2020 paper looking at in-flight dehydration, researchers suggested drinking between 100-300ml of water per hour on the plane, including the water you get in foods. It may mean you pee more often, but squeezing through the aisle is less annoying than feeling uncomfortable when you land. 

Images: Getty