Why do salad, rice and eggs make me bloated?

None of salad, rice or eggs is on the NHS list of foods that make you fart, so when they bloat you the cause often sits elsewhere: how much you ate and how fast, what came with them, or a gut that reacts to meals in general. In one study, lettuce made people’s tummies swell without adding gas.

I eat three eggs every morning, so I will admit to some bias on the last one. The research on all three is more interesting than the reputation.

Why does salad make me bloated?

Often it is not the gas. A team in Barcelona took 12 people who said lettuce gave them gas and a swollen tummy and looked at it two ways. In the lab, lettuce fermented by gut bacteria produced about as much gas as meat, and far less than beans. Then they scanned the patients during a lettuce bloat and compared it with a normal day. Their waists had grown by about 3.5cm, without a significant rise in gas in the bowel. What had changed was the diaphragm, which had moved down by about 7mm and pushed everything forward.

That is the same reflex behind a lot of visible bloating. In people who get distension, the diaphragm contracts and the belly wall relaxes, where it should be the other way round. The researchers concluded that correcting that response might do more than cutting foods out. A physiotherapy approach called pelvic floor biofeedback can halve bloating and distension symptoms, and you can ask your GP about a referral.

Salads are rarely only lettuce, though. Raw onion, coleslaw, broccoli and cauliflower, beans and chickpeas, and dried fruit such as raisins or apricots are all on the NHS list of foods that can make you fart. A big bowl of raw vegetables is also a large volume, eaten quickly at a desk.

Why does rice make me bloated?

Usually the portion, the pace, or the company it keeps. Rice has no gluten, which is found in wheat, barley and rye, so rice is not the trigger for coeliac disease. That leaves three things worth knowing.

Brown rice is high in fibre. NICE suggests it may help some people with IBS to limit high fibre foods, and names whole grains such as brown rice. If you swapped white for brown recently and the bloating started then, that is worth noting. Fibre that goes up suddenly can make symptoms worse.

Leftover rice is not the same as fresh. When cooked rice cools, some of its starch changes into resistant starch, which escapes digestion in the small intestine and reaches the large bowel whole, where bacteria can ferment it. In one study, rice cooled in the fridge for 24 hours and reheated had 1.65g of resistant starch per 100g, against 0.64g in freshly cooked rice. NICE suggests people with IBS reduce resistant starch, and says it is often found in processed or recooked foods. If yesterday’s rice bothers you and tonight’s does not, this may be why.

The sauce. Rice is often the base for a curry, a stir fry or a takeaway. Onions are on the NHS list of foods that make you fart, and fatty and spicy food are both listed as possible IBS triggers.

Why do eggs make me bloated?

Eggs give gut bacteria little to work with, so look at the rest of the plate first. In the UK food composition tables, a raw egg is 12.6g protein and 9g fat per 100g, with only a trace of carbohydrate. Fermentable carbohydrates, the FODMAPs, are one of the main things gut bacteria turn into gas, and eggs have almost none.

What comes with them often does. Toast brings wheat, which contains fructans, a FODMAP. Baked beans bring pulses. A fry up brings a lot of fat, and fatty food is one of the IBS triggers the NHS lists. Onions in an omelette add their own.

Two things are about the egg itself. You can be intolerant to any food, and a food intolerance usually shows a few hours after eating it. And eggs are one of the most common foods behind allergies, which is a different matter: an allergy can bring itchy skin or a raised rash, swelling of the lips, face and eyes, and wheezing, as well as tummy pain. Call 999 if your lips, mouth, throat or tongue suddenly become swollen.

What do these three have in common?

In each case the food on its own is not a strong suspect, which points back to the meal and to the gut.

In IBS, the nerves of the gut can be too sensitive to the way the bowel normally moves, so an ordinary meal can feel like a heavy one. Eating fast swallows air, and large meals add to bloating whatever is in them. If plain foods bloat you as much as rich ones, bloated after eating anything is the more useful page for you.

What should I do if one of these bloats me?

Keep eating it and write down what happens. Note the food, how much, how it was cooked, what was with it, how fast you ate, and when the bloating started. A week of dated notes will show whether the food is the pattern or only happened to be on the plate. The NHS says not to cut foods out without advice from a GP or a dietitian, because you can miss out on vitamins and minerals.

If you have been adding more salad, beans and whole grains to eat more plants, go gradually: more fibre made my bloating worse explains why, and does rice count as a plant point answers the other question people ask about rice. The bloating quiz can help you decide where to start.

See a GP if you feel bloated regularly, or if you have tried changing your diet and keep feeling bloated. That is the NHS’s advice, and it applies whatever food you suspect.