6 Truths about a gluten free diet

 Eighteen months ago, Ahmed Yearwood decided to go gluten-free. "A few years earlier, I'd given up processed foods and felt great," the 41-year-old business owner recalls. "I figured cutting out gluten would make me feel even better. Everyone told me I'd have more energy and lose weight." He lasted less than a month. "Everything was rice this and rice that—it was way too restrictive," he says. "And I didn't feel any different healthwise than I did before." Yearwood reverted to his former eating habits. "Some of the grains I eat have gluten, but I still feel amazing."

Just as fat was vilified in the 1990s and carbs have been scorned more recently, gluten—a protein found in wheat, barley, and rye—has become the latest dietary villain, blamed for everything from forgetfulness to joint pain to weight gain. "Gluten free" is a claim you see on everything from potato chips to bread to hummus—and even on cosmetics and laundry detergent.  Some people must avoid the protein because they have celiac disease—an autoimmune condition in which gluten causes potentially life-threatening intestinal damage—or gluten sensitivity. But less than 7 percent of Americans have those conditions.

According to a recent survey of more than 1,000 Americans by the Consumer Reports National Research Center, 63 percent thought that following a gluten-free diet would improve physical or mental health. About a third said they buy gluten-free products or try to avoid gluten. Among the top benefits they cited were better digestion and gastrointestinal function, healthy weight loss, increased energy, lower cholesterol, and a stronger immune system.

Yet there's very limited research to substantiate any of those beliefs, notes Alessio Fasano, M.D., director of the Center for Celiac Research at Massachusetts General Hospital in Boston. Unless you have celiac disease or a true gluten sensitivity, there's no clear medical reason to eliminate it, Fasano says. In fact, you might be doing your health a disservice. "When you cut out gluten completely, you can cut out foods that have valuable nutrients," he says, "and you may end up adding more calories and fat into your diet." Before you decide to ride the wave of this dietary trend, consider why it might not be a good idea.

A quarter of the people in our survey thought gluten-free foods have more vitamins and minerals than other foods. But a recent Consumer Reports review of 81 products free of gluten across 12 categories revealed that they're a mixed bag in terms of nutrition. "If you go completely gluten-free without the guidance of a nutritionist, you can develop deficiencies pretty quickly," warns Laura Moore, R.D., a dietitian at the University of Texas Health Science Center at Houston. Many gluten-free foods aren't enriched or fortified with nutrients such as folic acid and iron; the products that contain wheat flours are.

And it may come as a surprise to learn that ditching gluten often means adding sugar and fat. "Gluten adds oomph to foods—wheat, rye, and barley all have strong textures and flavors," says Angela Lemond, a registered dietitian nutritionist in Dallas and a spokeswoman for the Academy of Nutrition and Dietetics. Take it out of food that usually contains it and you might find that extra fat, sugar, or sodium have been used to compensate for the lack of taste. For example, the Walmart regular blueberry muffins we looked at had 340 calories, 17 grams of fat, and 24 grams of sugars. Gluten-free blueberry muffins from Whole Foods had 370 calories, 13 grams of fat, and 31 grams of sugars. Thomas' plain bagels had 270 calories and 2 grams of fat; Udi's plain gluten-free bagels had 290 calories and 9 fat grams. We found similar differences in all 12 food categories. It may not seem like much, but a few grams here and there can add up. A gluten-free bagel for breakfast and two slices of gluten-free bread at lunch means 10 to 15 additional grams of fat.

Gluten may actually be good for you. There's some evidence that the protein has beneficial effects on triglycerides and may help blood pressure. The fructan starches in wheat also support healthy bacteria in your digestive system, which in turn may reduce inflammation and promote health in other ways. One small study found that healthy people who follow a gluten-free diet for a month have significantly lower levels of healthy bacteria.

About half of the gluten-free products Consumer Reports purchased contained rice flour or rice in another form. In 2012 we reported on our tests of more than 60 rices and packaged foods with rice (such as pasta, crackers, and infant cereal). We found measurable levels of arsenic in almost every product tested. Many of them contained worrisome levels of inorganic arsenic, a carcinogen. We've done more testing to see whether there are some types of rice we can recommend as lower in arsenic than others, and whether other grains (gluten-free ones like quinoa as well as bulgur and barley) contain significant levels of arsenic. We've also done additional analyses of data from the Food and Drug Administration to determine arsenic levels in packaged foods that have rice.  

A 2009-10 study from the Environmental Protection Agency estimates that 17 percent of an average person's dietary exposure to inorganic arsenic comes from rice. That may be an underestimate, especially for people on a gluten-free diet. It's getting easier to find gluten-free foods that don't contain rice, but the majority of them do. "If you don't have to give up gluten, the likelihood that you'll consume a significant amount of arsenic following a typical gluten-free diet should give you pause," says Michael Crupain, M.D., M.P.H., associate director of Consumer Safety and Sustainability at Consumer Reports. In a 2014 Spanish study, researchers estimated the arsenic intake of adults with celiac disease. They devised a daily menu that assumed someone would eat rice or a rice product high in arsenic at every meal and snack. A 128-pound woman following such a diet would get 192 micrograms of inorganic arsenic per week from rice and rice foods alone. For a man weighing 165 pounds, it would be 247 micrograms. "These levels are close to 10 times the amount of inorganic arsenic we think consumers should get in their diets on a weekly basis," Crupain says.

More than a third of Americans think that going gluten-free will help them slim down, according to our survey. But there's no evidence that doing so is a good weight-loss strategy; in fact, the opposite is often true. In a review of studies on nutrition and celiac disease published in the Journal of Medicinal Food, researchers said that a gluten-free diet "seems to increase the risk of overweight or obesity." The authors attributed that to the tendency for gluten-free foods to have more calories, sugars, and fat than their regular counterparts.

People who have celiac disease often gain weight when they go gluten-free, Fasano notes. That's because the damage gluten does to their small intestine prevents them from digesting food properly. Their digestive system heals after they have given up gluten and they're able to absorb key vitamins and nutrients from the foods they eat, including calories. In a study of 369 people with celiac disease, 42 percent of those who were overweight or obese lost weight after almost three years on a gluten-free diet, but 27 percent of them gained weight. In another study, 82 percent of those who were overweight at the start of it gained weight.

What about those who say they got rid of their belly when they ditched the wheat? There's no evidence that it was due to cutting gluten. "If people lose weight on a gluten-free diet, it might be because they're cutting calories, eating less processed food or sweets, or cutting portions of starchy foods like pasta and bread," says Samantha Heller, R.D., senior clinical nutritionist at NYU Langone Medical Center. "Instead of a cookie, they're eating an apple. Instead of pasta, they're eating a high-fiber, gluten-free whole grain like quinoa. Eating more fiber helps satiety and may aid in weight loss."

For information on healthy ways to lose weight, read our diet plan buying guide.

Our research found that in every category except ready-to-eat cereal, the gluten-free versions were more expensive than their regular counterparts, about double the cost, and in some cases considerably more. For example, brownies made from the Duncan Hines regular mix cost about 8 cents per serving; Betty Crocker's gluten-free mix cost 28 cents per serving. The per-serving cost of Nabisco's Multigrain Wheat Thins is 31 cents; it's 57 cents for the company's gluten-free Sea Salt & Pepper Rice Thins. DiGiorno's Pizzeria Four Cheese frozen pizza is $1.38 per serving; Freschetta's Gluten Free Thin & Crispy Four Cheese frozen pizza is $2.50 per serving.

Why are foods without gluten more expensive? "One factor in the price dif­ferential may be attributed to the added costs incurred by the manufacturer to meet certification and labeling regulations," explains Andrea Levario, executive director of the American Celiac Disease Alliance, a nonprofit group.

If you're convinced that you have a problem with gluten, see a specialist to get a blood test to check for certain antibodies associated with celiac disease. You need to be eating gluten when the test is done to get a proper diagnosis, notes Peter Green, M.D., director of the Celiac Disease Center at Columbia University's medical school. If it's positive, then you should have an endoscopic biopsy of your small intestine to check for damage.

Your symptoms may also be a reaction to something other than gluten in your diet. "We commonly see patients who go on a gluten-free diet and feel better for a week or two," explains Joseph Murray, M.D., a gastroenterologist at the Mayo Clinic. "It may be the placebo effect or simply because they're eating less. For some, their symptoms come back, so they decide to drop another food group, and then a few weeks later, when they're still not feeling any better, they make an even more drastic change, like going completely vegan. By the time they enter my office, they're on a severely restricted diet and still have symptoms." The reason? It often turns out their condition wasn't celiac disease or even gluten sensitivity at all, but another condition, such as irritable bowel syndrome.

Some people may benefit from something called the low-FODMAPs diet. The acronym stands for fermentable oligo-di-monosaccharides and polyols. They're the carbohydrates fructose (found in fruit and honey); lactose (in dairy); fructans (in wheat, garlic, and onions); galactans (in legumes) and polyols (sugar-free sweeteners); and stone fruit like apricots, cherries, and nectarines. The diet is complicated, however, and you might need to work with a GI specialist or nutritionist to help you figure out which foods to eat.

A recent study in the European Journal of Clinical Nutrition looked at 158 food products labeled gluten-free over three years. It found that about 5 percent—including some that were certified gluten-free—didn't meet the FDA's limit of less than 20 parts per million of gluten. The products were tested before the FDA's rule went into effect last summer. Still, that standard doesn't stipulate that manufacturers must test their products before making a gluten-free claim. "Cross-contamination can occur," Levario explains. "Gluten-free products may be manufactured on the same equipment used for wheat or other gluten-containing products." That can also happen when wheat is grown next to other grains. For example, oats are often grown in or near fields where wheat has been grown. As a result, wheat finds its way into the oat harvest and contaminates its subsequent products.

There's no way to completely protect yourself, but you can call manufacturers. "They should be transparent about what tests they use to determine whether a product is gluten-free," says the study's author, Tricia Thompson, M.S., R.D., founder of Gluten Free Watchdog. "If they insist that it's proprietary information, that should set off an alarm."

Another concern is that some products, particularly chips and energy bars, that carry a no-gluten claim contain malt, malt extract, or malt syrup, which are usually made from barley. As the study notes, "some manufactures mistakenly believe that the only criterion for labeling a food gluten-free is that it tests less than 20 ppm gluten." The FDA also stipulates that the food can't contain an ingredient derived from a gluten grain that has not been processed to remove the gluten. For people with celiac disease, inaccurate claims can be damaging. As always, it's best to read the ingredients list.

If you must cut out gluten, be sure to do it the healthy way:

Get your grains. Whether you're on a gluten-free diet or not, eating a variety of grains is healthy, so don't cut out whole grains. Replace wheat with amaranth, corn, millet, quinoa, teff, and the occasional serving of rice.

Shop the grocery store perimeter. Stick with naturally gluten-free whole foods: fruit, vegetables, lean meat and poultry, fish, most dairy, legumes, some grains, and nuts.

Read the label! Minimize your intake of packaged foods made with refined rice or potato flours; choose those with no-gluten, non-rice whole grains instead. Whenever you buy processed foods, keep an eye on the sugar, fat, and sodium content of the product.