If you are holding a dinner party and do not have a request for a wheat-free meal from one of your guests, then count yourself lucky. Unless, of course, you are following such a regime as well, in which case everything from bread rolls to salmon en croute and summer pudding will be off the menu anyway.

With sales of wheat-free products in supermarkets booming — sales of Sainsbury’s freefrom products leapt from £72 million to almost £90 million last year — everyone from international celebrities such as Scarlett Johansson and Gwyneth Paltrow to our home-grown Suzanne Shaw are espousing the wheat-free cause.

While Shaw claims that she found wheat “hard to digest” and that giving it up led to “weight dropping off naturally”, this is where the reasoning behind going wheat-free becomes a bit murky. Some people seem to jump on the wheat-free bandwagon as a socially acceptable way of restricting an extensive range of foods in order to lose weight.

It is much easier to say “Oh, I can’t possibly have a piece of cake” if you play the wheat-free card. Others eschew wheat blaming it for an astonishing array of symptoms from bloating to skin problems and even migraines.

But there is no definitive clinical test that can tell you whether you are actually intolerant to wheat. The British Nutrition Foundation is sceptical about the recent surge in self-diagnoses as one of its nutritional scientists, Claire Williamson, explains: “There is no evidence that the true prevalence of wheat intolerance is on the increase. Wheat sensitivity probably involves a fair share of wheat aversion, which is a psychological rather than physical response to eating wheat-containing foods. We see wheat-free diets as a being a bit of a fad.”

Ursula Arran, a registered dietician and the spokeswoman for the British Dietetic Association, believes that even if the underlying cause is not physical we should not dismiss it: “If the link exists in a person’s mind that certain foods cause certain symptoms then clearly they will want to avoid these foods, even if there is no scientifically valid way of being sure a true intolerance exists. If this is the case, as a dietitian I can’t sit there and tell that person to keep eating the food they think is making them poorly.

“In such cases going wheat-free for a month is probably worth a try. If you feel better afterwards, then great. But bear in mind that a wheat-free diet is complicated and that you have to work that bit harder to eat well.”

Eating well may be at the crux of the matter. Michelle Berridale-Johnson, the editor of Food Matters, a magazine for people with food intolerances and allergies, has an unexpected perspective on the debate. “Research has shown that when people who believe they are wheat intolerant followed a generally healthier lifestyle, cleared the rubbish out of their diets and ate well, after two weeks, around 30 to 40 per cent felt a lot better following this advice alone. Those who didn’t were then given a diet free of wheat and dairy. Some felt significantly better indicating they may have genuinely been affected adversely by such foods. Those who did not feel better were referred for further investigations to get to the bottom on their problems.”

The problem could simply be that our systems cannot cope with the excessive loads of wheat-based foods that we consume each day. If we eat cereal or a croissant for breakfast, biscuits mid-morning, filled rolls at lunch, cake in the afternoon and pasta for dinner we are consuming significant amounts of highly refined wheat.

We risk developing a “transient intolerance”, which can be “cured” by cutting back to one or two wheat-based foods a day. But while many health professionals feel that wheat intolerance is hugely over-estimated, alternative nutritionists and therapists may be quick to dole out wheat-free advice to clients.

But be warned: wheat-free foods cost on average about two to three times more than their wheat-based equivalents. If you are convinced that you need to go wheat-free, try to eliminate all wheat-based foods for at least two weeks, then reintroduce some and observe whether your symptoms improved in the withdrawal period, and if they reappear once reintroduced.

Whether you need to go to these lengths will remain — until a test is developed — a matter for heated debate.

Coeliac disease is when the body’s immune system reacts to gluten in wheat, barley and rye. One in 100 people in the UK has the disease, which can be diagnosed by a blood test followed by a biopsy of your intestinal wall. Excluding all gluten from the diet will reverse symptoms.

Wheat allergy is rare and is triggered by wheat components other than gluten. Diagnosis can be made with a test called a radioallergosorbent test. However, diagnosis can still be difficult.

Wheat intolerance does not involve the immune system, which is why there is no definitive clinical test to prove its existence.

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