Henry Hunt said goodbye to gluten not because a doctor told him to, but because — like so many others — he decided he was better off without it.

"I diagnosed myself," he says, "because I'm really in tune with my body."

The Baltimore insurance salesman heartily endorsed his gluten-free diet recently while lunching at Sweet 27, a cafe that has similarly done away with the protein that's become the latest nutritional boogeyman — the new carb or fat or red meat. At the tiny Remington restaurant, the owner's wife says she can't tolerate gluten, the owner avoids it out of sympathy, and since working there, the cashier has decided that he must also be one of the people who can't eat it.

By some estimates, as much as a quarter of the country has cut back on gluten or eliminated it altogether. And yet, experts say, less than 10 percent of us have a real problem with gluten.

So everyone else? Those gluten-free muffins in your grocery cart are there for no good reason.

"I tell people, 'You don't have a reason to be on a gluten-free diet,'" says Dr. Alessio Fasano, director of the University of Maryland Center for Celiac Research. "They say, 'But if I want to? Am I doing harm?' I say, 'Absolutely not, beside the harm to your pocketbook.'"

In a world where Oprah's magazine gushes about a line of boutique gluten-free pastas and where people can go into one of Baltimore's trendiest restaurants and request the gluten-free menu, it's hard to realize that not long ago, few people had even heard of "gluten."

In the last few years, even food industry experts have been wowed by the deluge of gluten-free products coming on the market, and the money even people immersed in a recession have been willing to spend on them.

Packaged Facts, a market research company, had predicted that gluten-free product sales would hit $2.6 billion by this year. But the country hit that benchmark two years early. Now, some marketers say, spending on gluten-free products tops $6 billion a year.

It hasn't hurt that a number of celebrities have talked up the gluten-free lifestyle, including Victoria Beckham, Zooey Deschanel and Drew Brees. Gwyneth Paltrow blogs about it. Chelsea Clinton's wedding cake was famously gluten-free. Elisabeth Hasselbeck wrote a book called "The G-Free Diet."

At the recent Sundance Film Festival, one gluten-free snack maker, determined to woo stars, set up in the swag area alongside the high-end cosmetics and designer accessories.

Celiac disease is a genetic autoimmune disorder affecting less than 1 percent of the population. If people who have it eat gluten, which is commonly found in wheat, barley and rye, they risk damaging their digestive systems. Symptoms range from cramps to weight fluctuation to fatigue, migraines and osteoporosis. Untreated, it can be life-threatening.

Gluten sensitivity on the other hand, typically involves symptoms similar to celiac disease but less severe. Fasano estimates about 6 percent of the population suffers from this relatively new diagnosis.

If one has celiac disease, that pretty much means no bread, pasta, cake, pie or cereal. No cookies or crackers or candy. No sauce, dressing or breading

But here's where it gets tricky: Gluten-sensitive people need only be as gluten-free as it takes for them to feel OK.

And, Fasano will be happy to tell anyone — all those starlets included — if you don;t have celiac disease and you're not gluten-sensitive, you might as well enjoy that crusty wheat bread.

But who's listening?

Last year, 1,968 gluten-free products made their debut, according to Mintel's Global New Products Database. About the same number debuted in 2010.

At Wegmans, an entire frozen-foods case is reserved for gluten-free goods, including macaroni and cheese, pumpkin pie and muffins. Trader Joe's offers gluten-free rolls and cookies. When you order takeout Chinese food, chances are the soy sauce packet will boast its lack of gluten.