"I get so many calls for gluten-free flour, and I'm like, "'No, we love gluten! It's all gluten everywhere!'" laughs Emma Zimmerman. "But I think it's helped us out in some ways because people are so much more aware."
Emma, Jeff Zimmerman's daughter, takes care of Hayden Flour Mills' sales and, thus, spends the most time interacting with chefs and other customers. She knows firsthand about the battle between bread lovers and their anti-gluten counterparts, those who say that going gluten-free leads to better health and weight loss.
And though anecdotal evidence of the gluten-free diet's success abounds, ASU professor Glenn Gaesser, who has been doing research on grains for more than a decade, says the scientific proof just isn't there.
"Americans are historically very nutrition-dumb and gullible, so virtually anything can fly in terms of weightloss gimmicks and diets," he says. "So gluten-free became very faddish."
From a scientific standpoint, the gluten-free diet is a treatment for celiac disease, a digestive and autoimmune disorder that impacts the small intestine. For those affected by the disease, eating gluten can have severe health consequences, including skin rash, seizures, and depression.
It's estimated it affects about 1 percent of the population, though there has been no extensive research on the disease.
Another 5 percent to 6 percent may have gluten sensitivity or an allergy to the protein. But unlike those with celiac disease, which can be definitively identified through a blood test, there's no scientific way to identify gluten sensitivity.
Most cases are self-diagnosed by people who find that eliminating gluten from their diets has led to feeling better.
The scientific community, including Gaesser, has doubts as to whether it's really gluten that's to blame.
"I don't doubt for a minute that people might temporarily feel better," he says. "But that could be purely psychological. And it could be because they're cutting out wheat."
According to Gaesser, there haven't been long-term studies about the effects of a gluten-free diet on those who have neither celiac disease nor a confirmed gluten-sensitivity.
In other words, for the vast majority of the population, a gluten-free diet could have no health benefits at all.
One new theory is that it may actually be fermentable oligo, di, monosaccharides and polyols, or FODMAPS, that are the culprit. These short-chain carbohydrates aren't completely absorbed by the digestive system and have been shown in a scientific study to cause gastrointestinal distress in people with irritable bowl syndrome.
It is still unclear whether that means they could be harming other groups or the general population, Gaesser says.
Scientific basis or not, the gluten-free trend doesn't seem to be going away anytime soon. From 2011 to 2013, the industry grew by 44 percent, and it's expected to reach total sales of $1.5 billion by 2016.
"How this will play out, I don't know," Gaesser says. "My guess is that it will play out naturally. It will peak and then it will wane eventually."