We’ve all been there: sat in a restaurant trying to subtly unbutton a painfully tight waistband or snake a belt out of its loops – clothes that fit comfortably a few courses earlier now strain over an expanded belly.
That’s classic bloating. It’s quick, it’s dramatic – but you know you will have deflated by the morning.
However, not all bloating is so obvious. If you haven’t just tucked into a feast and your tummy feels bigger than usual, it can be more difficult to work out whether your extra roundness is air or belly fat.
In that case, there are a few tell-tale signs to look out for.
Bloating feels different to weight gain
If your belly seems to have grown, the first thing to notice is how it feels. Is it soft or firm? Does it stick out or flop down? Does it hurt?
“When you have a bloated tummy, it’s tight and hard and distended and can be a bit painful, whereas belly fat doesn’t feel like that,” explained Dr Karen Wright to BBC Science Focus. She is a senior lecturer in biomedicine at Lancaster University who specialises in gut health.
Dr Megan Rossi, a dietitian and nutrition scientist, adds that a bloated tummy tends to stick out – “what you might call a food baby” – under uncomfortable pressure.
But if your extra size is soft and isn’t causing any discomfort, it’s more likely to be a sign of recent weight gain.
Bloating comes and goes more quickly than weight
Another way to tell bloat from putting on weight is how quickly your belly has grown. Bloating can last as little as a few hours before you return to your previous size and shape, whereas weight gain is a slow and gradual process.
Rossi says that, if your tummy is flatter in the morning but tight and full by evening, that’s likely bloating – and Wright adds that weight gain becomes slowly apparent over time, as the number on your scale steadily increases.
“A bloated tummy is not going to change your weight very much, if at all,” she notes.
So, while bloating can cause daily fluctuations, changes to fat or muscle happen much more gradually.
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How your food choices can lead to bloating
If you’re still unsure whether your tummy has inflated or gained some extra padding, it might help to consider whether you’ve encountered any bloating triggers.
Wright says that one of the most common reasons we might get gassy is because we’ve swallowed air while eating quickly or drinking bubbly beverages.
“Some of that air might come out with some burping, but the rest will go with your food to your intestines,” she explains. “Then, it can get trapped – or sometimes it’ll pass through, and then you might have some flatulence.”
She adds that big meals and fibre-rich foods – such as lentils, beans and cabbage – can have a similar effect, by exaggerating a natural and healthy digestive process.
Rossi explains: “A little bloating after a fibre-rich meal is usually a good sign that your gut microbiome is active and thriving. This is because your bacteria produce gas when they digest fibre.”
So, lots of fibre – or just lots of food – can mean more gas is produced in the gut, and therefore more bloating.
But this process is highly individual. Rossi says that everyone’s guts react differently, even to the same foods – so you might balloon after chilli con carne, while your friend is set off by buttery garlic bread.
And Wright adds that if we go too far with any potentially aggravating food or drink, our guts likely won’t thank us.
That’s because our gut microbiomes rely on balance to function well. Too much of something – particularly if it’s sugary, fatty, fibrous, salty or alcoholic – might throw off this balance and lead to bloating.
If you’re not sure what’s at play, Rossi says that bloating in the upper abdomen is likely related to how you’re eating – i.e. too quickly, fizzy drinks and large meals – whereas bloating lower down suggests it’s the food that’s the problem.
What could make bloating more likely
If your recent eating habits don’t seem to have caused your belly to balloon, it could be something else. Your mind can play a role in your gut health too.
“We have what’s called a gut-brain axis, where microbes produce things that get sent to the brain, and the brain sends things back to the gut,” says Wright, explaining that stress and anxiety can throw off your gut microbiome’s balance and lead to bloating.
It’s also worth noting that some people’s hormones make them more prone to bloating than others – for instance, during the pre-period phase of the menstrual cycle, or during perimenopause or menopause.
And there doesn’t have to be a single obvious culprit at all. Rossi says that bloating can be triggered by a combination of up to 22 different food and lifestyle factors – including salty food, a food intolerance, fibre, dehydration and tight clothing – all of which could be playing a role.
What to do about bloating
So, if you’ve worked out that your extra bit of tummy isn’t weight gain but trapped air, what should you do about it?
Well, you could just wait it out. Since bloating usually goes away fairly quickly by itself, a joyful parp may come your way before long.
But if the air isn’t budging or is particularly uncomfortable, you could encourage it out with movement.
“It can be quite moderate, like going for a walk – but also some good stretching exercises can really help,” says Wright. “You can try massaging your tummy and moving it from side to side, to get that air moving down.”
And if your bloating is something you deal with on a regular basis, you might want to speak to your doctor.
“If your bloating is occasional or follows a high-fibre meal, it’s usually harmless,” says Rossi. “However, if it’s persistent or affects your quality of life, keep a food and symptom diary and seek support.”
Wright adds that, if your bloating lasts a long time or keeps coming back – or if it appears alongside other symptoms, such as constipation, diarrhoea, blood in your poop, or unintended weight loss – then “it’s always worth checking” with a doctor.
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