garbage can full of bread
Travis Rathbone for Reader’s Digest

I work with a lot of people who have stomach issues. One of the first things they ask is “Should I cut out gluten?” My usual answer: probably not. Here’s why.

For patients with celiac disease, ditching gluten—a protein in wheat, barley, and rye—is a must. In these people, gluten causes inflammation in the small intestines that can lead to malnutrition. But I’m concerned about the growing number of individuals who’ve adopted a gluten-free diet with no celiac diagnosis. Chances are you know folks like them: They had stomach issues, like bloating or pain, or fatigue and headaches. Then they stopped eating gluten and felt better. If they resumed eating it, symptoms came roaring back.

But new research out of Monash University in Australia suggests that gluten intolerance among people without celiac is far less common than previously thought—which I’ve long observed in my patients. It may be that other nutrients in grains, particularly carbohydrates called FODMAPs, trigger symptoms.

Does Gluten Intolerance Really Exist?

In the study, irritable bowel syndrome (IBS) patients who were on a gluten-free diet switched to a low-FODMAP diet. (This entails avoiding certain fruits, vegetables, grains, and legumes.) Participants all reported feeling better on the low-FODMAP diet. They were then told that gluten would be added back into their diets (they were given prepared foods), but they didn’t know when or how much. Certain people got a high-gluten diet; others, low-gluten; and still others got a placebo without any gluten. Most patients said they felt worse no matter which diet they were on. Here’s the real shocker: The placebo diet was identical to the soothing low-FODMAP plan, but subjects reported an uptick in symptoms. Actual gluten sensitivity occurred in only 8 percent of respondents. Translation: Gluten may make you sick because you expect it to. When you cut out foods with gluten—such as refined carbs—you also remove FODMAPs, which may be the true reason you feel better.

Meet the Real Culprit

Certain people have trouble digesting all or some FODMAPs: lactose (milk sugar), excess fructose (in apples, pears, high-fructose corn syrup, honey), fructans (in wheat, barley, rye, onion, garlic), galacto-oligosaccharides (in legumes), and polyols (in mushrooms, cauliflower). This group of carbohydrates can cause gas, bloating, fatigue, constipation, and/or diarrhea in those with sensitive stomachs.

So before you give up gluten, consider whether FODMAPs might be your real problem. Here’s how both affect common health issues.

• To treat a troubled tummy: A low-FODMAP diet may be better, especially if you eat gluten-free and still have stomach upset. That’s what I created with the book 21-Day Tummy, which offers a nutrition plan for weight loss and digestive distress. Your doctor can recommend other resources.

• To clear up headaches or fatigue: Gluten may affect such symptoms, but scientists can’t yet explain the mechanism. And FODMAPs may still be responsible. We know that a low-FODMAP diet alters the balance of gut bacteria, which could affect other areas, like the brain. I’ve had patients who’ve cut out s report drastic improvements in their energy and well-being.

• To stop overeating carbs: You may be better off focusing on healthy carbs than on gluten specifically. My favorite whole grains are quinoa and brown rice. Though they happen to be gluten-free, I like them because they’re also low-FODMAP and packed with nutrients.

Reader's Digest
Originally Published in Reader's Digest