A common reason people avoid gluten is to lose weight-an approach about 13 million people have taken, far overshadowing gluten avoidance for health issues.

To remove gluten from your diet, you have to stop eating wheat and foods that contain it, such as bread, pasta, cereal and crackers, which are all relatively rich in calories.

If you replace them with foods like fruit, vegetables and lean meats, you may naturally eat fewer calories and lose weight.

But if you replace them with gluten-free counterparts made with rice or other gluten-free flours, you're just substituting one carb for another and likely eating the same number of calories-possibly more-so you won't lose weight.

There's also a risk that if you're removing wheat from your diet, whole grains may go by the wayside too. There are many benefits to whole grains-both gluten-containing and gluten-free.

Large-scale studies show that people who eat a lot of whole grains instead of refined grains are less likely to gain weight. Eating whole grains may also help lower cholesterol and reduce your risk of heart disease.

"Weight gain on a gluten-free diet can be a problem," says Pamela Cureton, a registered dietitian at the Center for Celiac Research at MassGeneral Hospital for Children, though it depends on the nature of the diet. Fruits, vegetables, lean meat and a range of whole grains, including quinoa, oats and brown rice, are all gluten-free.

But when a gluten-free diet is heavy on highly refined and processed carbs, such as white rice, rice crackers and gluten-free snack foods like pretzels, chips, doughnuts and cookies, weight gain may be an issue. These foods, after all, aren't that different from junk food made with wheat flour.

This story was produced in collaboration with the Food & Environment Reporting Network, a non-profit investigative journalism organization.