The condition impacts people's quality of life - from their jobs through to sport and travelling.

Shepherd says the condition (also known as IBS) includes symptoms of excess wind, bloating or stomach distention, abdominal pain and changes to bowel habits.

The symptoms can be similar to those that people with coeliac disease experience. So similar, in fact, that when Shepherd was experiencing symptoms as a 20-year-old, her doctor suggested she had IBS before the diagnosis of coeliac disease was made.

Shepherd was studying for a degree in dietetics at the time, so the diagnosis spurred her on to devote her work towards treating food intolerances.

Eighteen years later and Shepherd has just had her ninth book published, Low FODMAP Recipes, which is based on the low-FODMAP diet for people with IBS and coeliac disease.

Although Shepherd developed the FODMAP diet in 1999, she says the diet is in the early stages of general acceptance - much like how the gluten-free diet slowly became accepted in the early 1990s.

FODMAP is an acronym for the naturally occuring sugars that people with IBS have difficulty with as they are not absorbed in the small bowel. These are fermentable oligosaccharides, disaccharides, monosaccharides and polyols, found in everything from apples and wheat to garlic, onions and milk.

Shepherd says there has been a marked increase in the number of people she sees suffering the effects of IBS.

"People are a bit happier to talk about their symptoms these days," she says.

The 38-year-old now gets emails from across the world from people who say the FODMAP diet has changed their lives for the better.

She recalls how a client had ambitions to be a professional golfer, and has only just returned to the course after years of being unable to complete a round because of IBS.

Shepherd says the 150 meals inside Low FODMAP Recipes are easy to make and delicious.

"It's an everyday cookbook, people don't need to be a gourmet chef," she says.

"I like to show people more of what they can have than what they can't have."

There are even versions of classics such as lasagne - without trigger foods such as onion, garlic or milk.

"There's no essential nutrients that are missing - if anything, it makes cooking easier."

Shepherd has also reworked recipes that were published in previous books Irresistibles for the Irritable.

"The recipes need refreshing as we're always finding out more - like we never used to know mushrooms could cause problems, so I've had to tweak them out of the recipes."

Shepherd advises those who think they may have IBS to see a dietitian for individual advice. 

Low FODMAP Recipes by Dr Sue Shepherd, Penguin, $35. See www.shepherdworks.com.au.

BARBECUED SALT AND PEPPER SQUID WITH GARDEN SALAD

Have you seen this dish at restaurants and wanted to try it at home? It isn’t hard to do. Just grab a few fresh ingredients and follow Sue Shepherd’s recipe. Serves four. 

Ingredients

8 medium squid hoods, well-cleaned and cut into quarters

1 tablespoon garlic-infused olive oil

2 tablespoons olive oil

teaspoon salt

Freshly ground black pepper

Garden salad

150g lettuce leaves

cucumber, thinly sliced

1 avocado, sliced

2 sticks celery, thinly sliced

green capsicum, seeded and sliced

1 cup (50g) snow pea sprouts

Dressing

3 tablespoons olive oil

1 tablespoons fresh lemon juice

1 tablespoon garlic-infused olive oil

 teaspoon brown sugar

Salt

Method

• Using a sharp knife, score the squid hoods with a one-centimetre crisscross pattern. Take care not to cut all the way through – just about  of the way. 

• Mix the olive oils, salt and pepper in a large bowl. Add the squid pieces, toss to coat, then cover and refrigerate for three to four hours. 

• Shortly before you’re ready to eat, combine the lettuce, cucumber, avocado, celery, capsicum and sprouts in a large bowl.

• To make the dressing, place all the ingredients in a small screw-top jar and shake well to combine.

• Preheat a barbecue or chargrill pan to high (or use a non-stick frying pan over high heat). Cook the squid for three to four minutes or until curled and light gold.