As more and more of your friends go gluten-free, you may be wondering: Is there something to this latest diet craze? Is gluten-intolerance a thing? Is it getting more common?

The answer is simply no.

Only about 1 percent of Americans actually have coeliac disease, the rare genetic disorder that makes people intolerant to gluten, and that number is not on the rise. In other words, in a room of 100 people, chances are one has celiac.

In fact, a study published this month found that the prevalence of celiac has remained basically unchanged since 2009.

And as for all those people who say they don't have celiac but are just 'sensitive' to gluten, a 2013 study out of Monash University suggested that this probably isn't real.

So what's really going on when people stop eating gluten?

Alan Levinovitz, an assistant professor at James Madison University who studies the intersection between religion and medicine and the author of the book The Gluten Lie, says it essentially comes down to a mix of psychology and behavioural change.

In the book, Levinovitz interviews Monash University director of gastroenterology Peter Gibson, who helped write the 2013 study concluding that non-celiac gluten 'intolerance' was probably not a thing.

Gibson says the real reason that many people who have cut gluten claim to feel healthier afterwards is simply because they have changed their diet.

"I've noticed [this] lots of times, even with family members," Gibson tells Levinovitz.

"They have decided they're eating a lot of takeaway foods, quick foods, not eating well at all. They read this thing about gluten-free, and then they're buying fresh vegetables, cooking well, and eating a lot better."

In other words, while cutting gluten may seem like it helps you lose weight or clears up your complexion, the reality is that 500 other things could be the real cause.

"Blaming the gluten is easy, but you could point to about a hundred things they're doing better," Gibson adds.

But this can be a tough pill to swallow.

"When it comes to food sensitivities, people are incredibly unwilling to question self-diagnoses," Levinovitz writes.

"No one wants to think that the benefits they experienced from going gluten-free … might be psychological."

On top of that, connecting what we've eaten to physical symptoms is incredibly difficult. Not only have studies shown that we have trouble remembering what we ate when we ate it, we're also poor judges of what's healthy and what's not.

So rather than jumping to self-diagnose, see a doctor. And stick to the science.

This article was originally published by Business Insider.