Why you don't need to jump on the gluten-free bandwagon
Forget the hype - there is no good evidence that this overpriced food fad will give you a flawless physique
Complete a session at many of the most exclusive and model-laden gyms and, before the sweat glistening on your body has had time to evaporate, you are likely to be handed a gluten-free recovery ball to help you nibble your way back from fatigue.
What is now considered to be the optimal fuel for a flawless physique is a far cry from what was devoured a decade ago in the name of fitness. Few would consider carb-loading pasta, bread, or bagels, and the main reason for that is they contain gluten.
The protein, found in wheat, rye and barley, has been demonised to such an extent that it vies with sugar as the most reviled of ingredients. It is blamed for sluggishness and fatigue, and for slowing workout progression, not least the attainment of the ultimate prizes: washboard abs and lifted buttocks.
At the likes of London's Grace Belgravia - the women-only private members' gym where regulars are said to include the ultra-fashionable Delevingne sisters - in Knightsbridge and Triyoga's Retreat Café in Soho, great emphasis is placed on staying gluten-free but the message is no longer a secret kept by the elite.
About 13pc of Britons are thought to avoid gluten and the Irish market for gluten-free foods is growing fast. A Mintel report found that one-in-10 food products launched in 2014 were gluten-free, almost double the amount of two years previously.
It was revealed this week that supermarkets are charging a premium for such produce. Research carried out for the Channel 4 programme Supershoppers found items marked gluten-free were up to 200pc more expensive than basic versions of the product, even when they didn't contain gluten either.
Many of the new launches target the gym market, with gluten-free energy bars and shakes, whey powders and yoghurt-topped rice cakes.
You are unlikely to get a sniff of gluten on the menus of the juice bars adjoining the chicest boutique studios. The celebrity trainer James Duigan's Clean and Lean café at his new Bodyism gym in Notting Hill offers food that "has been created to nourish your body and feed your soul", ie, devoid of gluten.
"Even if you haven't been diagnosed as intolerant, it's worth considering that often foods containing gluten are not particularly healthy for you," says Duigan. "If you refrain from eating gluten your digestion will improve and you will experience less bloating."
The trend has been embraced at sport's highest levels.
Last year, a study of 1,000 competitive sports people in Australia found 41pc to be following a gluten-free diet. Some did so because they assumed it was a healthy step, others believed they had an allergy or intolerance, even though only 13pc of the participants had been medically diagnosed as such.
Andy Murray tried cutting it out, while Paula Radcliffe has spoken about removing several foods from her diet, including those containing gluten.
In his book Serve to Win, Novak Djokovic attributed his success to going gluten-free. "Mentally, you'll be fresh, you'll be happier, you'll be calmer," he enthused. "Physically you'll be stronger, faster, your muscles will work better."
There's no doubt that it can alleviate severe problems for those who suffer from coeliac disease, many of whom are undiagnosed.
It's a condition in which the immune system reacts to gluten, eventually damaging the lining of the small intestine and inhibiting the absorption of nutrients.
It can cause anaemia, weight loss, fatigue, bloating and pain unless gluten is removed from the diet.
Yet Steve Mellor, the director of Freedom2Train based at Claridge's in London, says that people are blaming gluten for symptoms when it is not the underlying cause.
"It's trendy and cool, so people jump on the bandwagon. There's lots of research that suggests that people are self-diagnosing gluten intolerances or sensitivities. It's not the epidemic that people perceive, but an industry of gluten-haters is being fuelled by over-zealous self-diagnosis regarding some generic symptoms and celebrities endorsing gluten-free diets."
What rankles among scientists is the lack of convincing proof that cutting out gluten is helpful. "At present there is no evidence to suggest fitness can be improved in any way when following a gluten-free diet," says Hannah Sheridan, a sports nutritionist at the University of Birmingham's High Performance Centre.
"There's this widespread belief that GI discomfort and bloating is caused by gluten, but it appears that other nutrients in gluten-rich foods are more likely responsible for GI symptoms, not gluten itself."
She adds that top athletes "are rarely encouraged to follow a gluten-free diet unless really necessary".
Last month, the Australian scientists who had assessed the prevalence of gluten avoidance in athletes set out to determine whether there are any fitness benefits in gluten denial. In a joint investigation with the Canadian Sport Institute in British Columbia, Dr Dana Lis carried out the first randomised, double-blind trial.
A small group of cyclists embarked on a gluten-free diet for two weeks. However, unbeknown to them, during one of the weeks they would be consuming fairly large amounts of gluten. It came in the form of an energy bar developed by the scientists in both gluten-loaded and gluten-free varieties that were indistinguishable in taste.
Throughout the trial, the subjects completed daily reports about their health and continued exercising as normal. After each week on the differing diets, they returned for the researchers to check any changes in gut inflammation and to complete a time trial on the laboratory bikes.
"It's easy to forget that many of the foods that contain gluten also contain carbohydrate, which remains the main source of energy for both endurance and high-intensity exercise," says John Brewer, professor of applied sports science at St Mary's University, Twickenham.
"Even if you are in training for a 5km fun run and decide to cut out gluten foods, you run a risk of depleting your energy reserves and suffering from a downturn in performance, along with poor recovery and higher levels of fatigue."
This happened to Andy Murray, who complained that the few months he spent on a gluten-free diet left him drained.
"I lost all my energy and felt so weak," he said. "I didn't feel it helped me at all, so I just went back to doing what I did before."
Slowly, it seems, the tide against gluten is beginning to turn. Dalton Wong, the director of Twenty Two Training whose clients include Jennifer Lawrence, says if your aim is to get fitter "it's important to keep gluten in your diet".
For most of us pursuing a better body, it's futile to indulge in such things as gluten-free power-balls.
"It's absolutely not worth the effort," Wong says. (© The Times)