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On a warm spring afternoon several weeks ago, TV host Jimmy Kimmel, as part of a segment for his Jimmy Kimmel Show, had correspondents wander the streets of Los Angeles, asking various residents the simple question -- "are you gluten free?" If a respondent replied affirmatively, that they were, in fact, gluten free, the inquiry was followed up by another question: "what is gluten?" Admittedly, this was not a scientifically valid sample, but of the Angelinos whose interviews were broadcast, not even one could correctly answer what gluten is. Only one was able to offer an explanation as to why she had made the decision to cut gluten out of her life, replying (incorrectly) that "it (gluten) makes you fat."

As a medical doctor, I should have marveled at the willingness of people to make such a major health decision without knowledge to guide their choice, but I did not. Both in my medical practice, and among friends, gluten-free is rapidly becoming a mainstream dietary choice.

Surveys in 2013 showed that the proportion of Americans interested in a gluten free diet was almost 30 per cent and that the market for gluten free food in the USA had reached $4.2 billion annually -- a 28 per cent compounded annual growth rate from 2008. All this has occurred despite little evidence that gluten-free diets have any proven health benefits. In fact, the British Columbia Medical Association in 2013 went so far as to issue the following advisory: "There is no need for patients to avoid gluten" since "most of the evidence against wheat or gluten is unsubstantiated by science."

So what is gluten and how did we get to this point?

Gluten (from the Latin word for "glue"), a complex of two proteins, gliadin and glutenin, is found in wheat, oats, barley, and spelt. Gluten makes dough sticky and elastic, allowing it to maintain its shape and chewiness while it rises. In the 1950s, Celiac disease, a condition affecting 1 per cent of the North American population, characterized by chronic diarrhea and failure to thrive in children, was found to be due to an inability to digest gluten. Thus, gluten free diets came into being as a medically necessary, niche product.

This changed dramatically in 2011, when a researcher, Peter Gibson, conducted a study of 34 non-celiac individuals, finding that those subjects on a gluten free diet experienced less pain, bloating and fatigue than subjects on a diet with controlled levels of gluten. This lent sudden credibility to a new condition -- Non Celiac Gluten Sensitivity (NCGS), whose only diagnostic criterion was the opinion of non-celiac patients that they felt better after cutting gluten out of their diet. No objective test has yet been devised for this condition and no biological abnormality has been discovered among those suffering from it.

The creation of a new medical diagnosis, which individuals could apply to themselves based on purely subjective criteria, has been a Pandora's box, rapidly snowballing into an avalanche of self-diagnosed cases. A European study, in 2012, found that 28 per cent of the people they surveyed self-diagnosed as NGCS. To put this in perspective, asthma, one of the most prevalent health conditions in existence, affects only 8.4 per cent of the North American population.

Gluten free -- Bad for your wallet AND bad for your figure

Research conducted by Dalhousie University, in 2008, studied the price differences between a basket of 56 gluten free grocery items and their regular, gluten filled competitors, and found that the price of the gluten-free basket was, on average, an incredible 242 per cent higher than the basket of standard items. Given that the average household in Canada spent $5,572 on groceries in 2012, this translates to a potential cost of over $13,000 per year for a typical household to go gluten free, a whopping amount by any measure!

Additionally, gluten-free foods are often significantly higher in fat and calories than their standard counterparts. For example, a major brand of gluten free sliced white bread was found to have 2.2 grams of fat and 80 calories per slice, compared with only 1 gram of fat and 58 calories per slice in that same brand's regular loaf. Similarly, a popular brand of gluten free chocolate chip cookies packed 90 calories and 6 grams of fat per cookie versus a gluten filled competitor with only 53 calories and 2 grams of fat per cookie. There can be little debate, with numbers like these, that gluten free is a poor strategy if one seeks to lose weight.

The latest evidence -- gluten sensitivity may not even exist

The newest hit against the gluten free movement comes from Peter Gibson, the very same researcher behind the 2011 study that first supported the existence of NCGS. Professor Gibson, concerned by the lack of any physiological abnormality to explain the findings of his 2011 work, as well as by limitations in his previous study methodology, repeated his older work, this time using 37 subjects already diagnosed with NCGS.

All subjects were rotated through three test diets -- high gluten, low gluten, and gluten-free. The results of this repeat study, shockingly, were the opposite of the 2011 research. Subjects reported worsening dietary symptoms no matter what diet they were switched to, including the gluten-free diet. Professor Gibson concluded that a "nocebo" effect was to blame, a phenomenon whereby subjects feel worse when they believe they are receiving no therapy, even if they are actually receiving treatment. The final conclusion of the study: NCGS likely does not exist as a disease entity.

So -- if your doctor turned to you one day and diagnosed you with a dietary condition that research suggests doesn't exist, for which there was no objective laboratory test, and for which treatment would cost your household thousands of dollars per year, while raising your fat and calorie intake with no measurable health benefits, would you say yes? I wouldn't -- and neither should you. And I would never recommend such a treatment to my patients.