Fart, fluff, blow off, trouser cough, flatulate, wind, bottom burp, taking fluffy for a walk, I think I can smell popcorn. Who decorated the air. We have lots of expressions for reverse expulsions.

Everybody does it and there's a simple reason for flatulence says Jane Scott, an accredited dietician at Curtin University and regular food and diet expert on South West Mornings.

"The main trigger for flatulence is high fibre food," she said. "It's one of the consequences of eating a healthy diet."

The reason is partly because the fibre is difficult for the body to digest. Once in the large intestine, the colon, gut bacteria ferment the fibre to break it down.

Gas is produced and also fatty acids which are good for keeping the lining of the colon healthy and for preventing colon cancer.

Farting is a sign of normal bowel health, says Jane. In hospital, post-operation, nurses will listen for bowel sounds.

"They want to hear some rumbling and some growling down there to know that your bowel is working."

Gas and smell.

"There's the food that causes the gas and there's the food that causes the smell," Jane pointed out.

"Interestingly, not everyone has smelly farts. It depends on the gut bacteria you have."

Smelly foods contain sulphites, she explains. Those more likely to cause odiferous emanations are the brassicas: cabbage, broccoli, brussel sprouts, and alums which are onions, leeks and garlic.

"Any fibre in the food will contribute to gas but it seems to be beans and lentils that are notorious.

"They can be more volatile."

Think Blazing Saddles.

Discomfort

Beans such as chick peas can cause cramps for some people, says Jane. If cooking with the raw beans, she suggests soaking them overnight, drain the water then cook them long and slowly.

"Drain again and rinse them and you get rid of the oligosaccharides which is what is in these foods that is making them hard for the body to digest."

Canned beans are already soaked and Jane recommends rinse them two or three times to remove the starchy liquid that contains the oligosaccharides.

An alternative to whole chick peas could be hummus where the beans are ground and the fibre is broken down.

Any beans can be made into a dip, says Jane. "Butter beans make a lovely dip with lemon juice and olive oil."

Avoid the sudden clean out

Suddenly adding a lot more fibre in your diet, will cause more flatulence until the body gets used to it. "Gradually increase the intake," is Jane's advice.

If the added fibre is still causing problems, cut back a little bit.

"Dried beans are a great source of fibre. Half a cup of chick peas can provide a third of our fibre needs for the day.

"A little goes a long way."

Food intolerance can also cause excess bottom burps. Some people have problems with foods that contain sugar, either naturally or added, such as like fruit.

"They may not have enough enzymes that are needed to help digest those foods."

Seasonal gorging on delicious fruit such as apricots or cherries will do the trick, says Jane.

Hang on or let go

Apart from cramps and feeling bloated and uncomfortable, gut gas isn't going to harm you, says Jane.

"If you do get cramps, the release comes when you release the gas."

Better out than in.