That question is at the center of a vexing health debate pitting some experts who say eliminating gluten confers a bevy of health benefits against others who argue there is no proven benefit except for the small percentage of people with celiac disease, whose bodies can't process the protein, The Wall Street Journal reports. 
 

Many gluten-free foods contain fewer vitamins, less fiber, and more sugar, critics note. But advocates of gluten-free foods argue that many of those products are nutritionally the same or better than their gluten-containing counterparts — even for individuals without celiac disease. The nutritional composition of Chex cereal, for example, didn't change when General Mills removed the gluten and may be a healthier option.
 

Even critics agree that not all gluten-free products are loaded with sugar and other unhealthy ingredients. But many food industry executives interviewed by The Journal conceded that a gluten-free diet is best followed by those who have a medical need.
 

A decade ago, few Americans had heard of gluten. Today, almost a third are trying to avoid the protein found in grain, by some estimates. In growing numbers, the world's biggest food makers and restaurants are retooling recipes and adding labels to tap into the trend, resulting in a multibillion-dollar industry built around gluten-free products.
 

A spate of books in the past decade has fueled suspicion of the food industry — from the ingredients companies use to how they treat farmland and animals. First lady Michelle Obama has made healthy eating a cause celebre. And Facebook has more than 1,000 groups with "gluten free" in the name, including a dating group called "Gluten-free singles."
 

In response, companies have churned out new foods, including not only gluten-free products but others labeled "low carb," "all-natural," "organic," "non-GMO," "dairy-free," "probiotic," and "hormone free."
 

Experts say new healthier food options have had a positive impact on the American diet. But we still eat an average of 459 more calories a day than we did 40 years ago, federal health statistics show. More than a third of adults in the U.S. are obese and 29 million U.S. adults have diabetes. Some health experts say the multitude of confusing options is part of the problem, including the gluten-free craze, The Journal reports.
 

"Food corporations have figured out how to adapt their foods to become solutions to health problems and at the same time capitalize on the confusion itself," said food historian Abigail Carroll, author of "Three Squares: The Invention of the American Meal."

Up to three million Americans suffer from the hereditary condition known as celiac disease, which can be diagnosed with a blood test. The National Foundation for Celiac Awareness says research shows another 18 million Americans have gluten sensitivity, experiencing discomfort without the intestinal damage.

The Food and Drug Administration has set labeling standards defining how much gluten could be in products labeled gluten-free, amplifying interest further.
 

Some doctors and celebrities began touting the benefits of gluten-free duets to address chronic conditions, boost weight loss, and increase energy. Today, gluten-free products can be found in every traditional supermarket and many restaurant menus. There's even gluten-free dog food. Global retail sales of products specifically formulated to be gluten-free have nearly doubled since 2007 to $2.1 billion last year, according to The Journal.
 

Many nutritionists say their biggest concern centers on the plethora of gluten-free snacks and desserts that exists today.
 

"Ten years ago a gluten-free diet would have helped you lose weight because you'd have cut out a lot of products like muffins and bread," said Margo Wootan, director of nutrition policy at the Center for Science in the Public Interest, a Washington, D.C., advocacy group. "The gluten-free fad has actually undermined people's health because now there are gluten-free varieties of all that junk food. Whether your doughnut is gluten-free or not, it's still a doughnut."
 

Becca Walker, a geology professor in Los Angeles, tells The Journal her health has improved since she went gluten-free. She says she was having gastrointestinal symptoms and general sluggishness about three years ago. But since eliminating the protein from her diet, she says her energy level has increased, her abdominal discomfort subsided, and she has lost five to 10 pounds.

"I feel better so I don't care why," Walker said.