Touted by everyone from the Pillsbury Doughboy to Miley Cyrus, gluten-free foods have entered the mainstream. Even Twinkie is considering jumping in a market estimated by research group Packaged Facts to be worth more than $4.2 billion in sales this year.
And last month, the Food and Drug Administration clarified its rules on what qualifies as gluten-free, which could lead more marketers to start labeling products that way -- including those that have never contained gluten. PepsiCo's Lays, for instance, is in the midst of a multiyear effort to certify its chips as being under the FDA limit for gluten-free labeling.
But does the trend have staying power? The answer lies beyond the relatively small market of 3 million Americans diagnosed with celiac disease who must avoid gluten, a protein found in some grains, including wheat, barley and rye. A much larger audience appears to be motivated by the growing -- and controversial -- perception that gluten causes all kinds of health problems, from weight gain to arthritis.
Snagging those types of consumers likely explains the big bets some marketers are making on gluten-free line extensions. Products launching in recent months include Nabisco Rice Thins, Pillsbury gluten-free dough and a line of Goodbye Gluten bread and wraps by baking giant Grupo Bimbo.
Packaged Facts predicts the U.S. gluten-free market will reach $6.6 billion in annual sales by 2017. That report came before the FDA set a threshold for a trace amount of gluten that could be contained in gluten-free-labeled foods. The regulations "give it a stamp of credibility," so major food companies that have "been on the fence now know what they can and cannot do," said Phil Lempert, a food-industry analyst who runs SuperMarketGuru.com.
Still, he predicts that "the bubble will burst" in a couple years. "Gluten-free products are expensive, so that will drive shoppers away from buying them once they realize little or no benefits from the diet." For instance, Betty Crocker gluten-free chocolate- brownie mix costs 38¢ per ounce, compared with 16¢ per ounce for regular fudge-brownie mix, according to prices posted on NetGrocer.com.
The market's long-term prospects might come down to the science, which remains unsettled. Everyone agrees that people with celiac disease should avoid gluten. But another diagnosis is rising in popularity called "non-celiac gluten sensitivity," though there is no medical test for it and estimates of its prevalence vary widely. "Science has shown that there is something going on, but we don't know what," said Carol Shilson, executive director of the University of Chicago's Celiac Disease Center. She added that there is new research coming out that suggests gluten might not be what is causing problems for this population.
Then there's a third segment of the population that attributes even broader health benefits to gluten-free diets, like helping with weight loss. Only 2% of shoppers who buy gluten-free foods do so because they have celiac disease, while 59% said they buy such products because they think they're more healthful, according to a 2013 shopper survey published by the Food Marketing Institute, which represents retailers.
Some theories blame wheat in general for an assortment of health ailments. One influential critic is Dr. William Davis, a cardiologist whose 2011 book "Wheat Belly" argues that modern, mass-produced wheat causes problems ranging from arthritis to schizophrenia.
The Wheat Foods Council, an industry trade group, is fighting back with an educational campaign targeting dietitians and nutritionists. After Dr. Davis appeared on the "Dr. Oz" show last year, the council responded with a letter to the show criticizing the book: "Research has shown that an overly restrictive diet, such as the one proposed in "Wheat Belly,' can not only be unhealthy, it is also not sustainable long-term," the letter stated, adding that "cutting out wheat puts dieters at risk for getting adequate fiber."
"People are using [gluten-free] as a fad diet when [celiac disease] is a very serious disease," said Judi Adams, the wheat council's president and a registered dietitian. "Would they go on a kidney-disease diet if they didn't have kidney disease?" She attributed the rise in popularity to celebrities who have embraced gluten-free diets as cure-alls. Among them is Miley Cyrus, who in a tweet last year said: "Everyone should try no gluten for a week! The change in your skin, physical and mental health is amazing!"
Marketers have been careful not to engage too much in the medical debate, although "gluten-free" labels appear prominently in some ads and in stores. General Mills, which offers more than 300 gluten-free lines including Pillsbury dough, said in a statement that "as with all of our brands, we leave the ultimate choice with the consumer."
For its Chex cereals, which began reformulating its lineup in 2008, Big G does tout its gluten-free benefits with a TV ad featuring a fan praising the brand for doing "the impossible" by making gluten-free cereals in a "bunch of yummy flavors."