The Low-FODMAP Diet Vs Gluten-Free: Which Is Better?

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Gluten-free is one of the biggest food fads we've ever seen: Gluten-free packaged foods now line grocery store shelves, and gluten-free bakeries and full restaurants have popped up nationwide. Much of this market is centered on the idea that at least 18 million of Americans have non-celiac gluten-sensitivity (NCGS), meaning that consuming gluten — a protein found in wheat, barley, and rye — gives them gas, cramps, bloating, or diarrhea. This is different from celiac disease, an autoimmune condition that makes avoiding gluten absolutely necessary. For people with NCGS, ousting gluten from their diet simply makes them feel better.

But now doctors are seriously doubting whether NCGS is really all that common. A landmark study from last year turned out some very convincing evidence that gluten may not be the culprit making so many people sick. Instead, it is likely a large class of carbohydrates called FODMAPs.

"FODMAPs are basically carbohydrates or sugars found in a variety of foods," says Dr. KT Park, a gastroenterologist at Stanford University School of Medicine. "These include fructose, found in fruits, honey, and high-fructose corn syrup; fructans, found in wheat, onions, and garlic; galactans in beans, lentils, and legumes; polyols in sweeteners and certain fruits; and lactose in dairy."

FODMAPs aren't new, of course, but doctors and dietitians are just starting to understand them. They're learning that while some people's digestive systems can handle FODMAPs just fine, many others' can't. "FODMAPs are highly water retentive, meaning that whenever you ingest them, water is pulled into the intestinal tract as the food courses from your stomach to the intestines," Park says. "That is what causes symptoms like bloating, gas, cramping, and diarrhea."


It makes sense that FODMAP sensitivities have been so widely mistaken for NCGS. "When people with FODMAP sensitivities pull gluten out of their diet, they do feel better," say Dr. Amy Burkhart, an integrative medicine physician in Napa, California. "But we come to find that it's the carbohydrate portion of wheat, not the gluten, that bothers them. They're also bothered by the carb portion of other foods, but because wheat is such a predominant part of the American diet, by eliminating it, they usually see big improvements. They get better — just not all the way better."

But this doesn't mean that NCGS isn't real, Burkhart insists. "It's been misconstrued in the media that NCGS is total baloney, but there are still people who truly have a problem with gluten," she says. "So it's not that NCGS isn't real. It just might not be as common as once thought. And maybe it should be reclassified as part of a new, wider condition that uses a more umbrella term."

Doctors have a lot more to learn about FODMAPs and their role in GI issues. But many are already putting their patients on low-FODMAP diets — and seeing huge success. "I've had many patients who thought they had NCGS go on a low-FODMAP diet, and they feel so much better," Park says.

But following a low-FODMAP diet is a beast, to say the least. Along with ditching wheat, you have to avoid apples, onions, garlic, mushrooms, watermelon, cauliflower, cashews, beans, soy foods, pickles, milk, ice cream, and anything with high-fructose corn syrup. And that's just a start. "When beginning this diet, many people feel overwhelmed," Burkhart says. "But the improvement in symptoms can be so dramatic that patients are very willing to stick with it, even though it's challenging. And as with any lifestyle modification or dietary change, it becomes easier over time. I've seen some pretty dramatic turnarounds with this diet — it can be absolutely life changing."


Burkhart also says that the longer you're on a low-FODMAP diet, the more liberal you can be about what you eat. "I've seen patients become more tolerant to FODMAPs over time, and they can usually add a few foods back in," she says. "The theory is that the overall immune system and the gut microflora have improved, making it easier to tolerate these foods."

But before you try a low-FODMAP diet, you need to visit your doc. Burkhart says it's crucial to get tested for celiac disease, inflammatory bowel disease, food allergies, or other underlying conditions before you begin eliminating foods from your diet. If those tests come back clear, have your doctor refer you to a gastroenterologist or registered dietitian who's familiar with low-FODMAP diets. FODMAPs may or may not be your issue, but an expert can help you figure it out and find the best course of action. "One size does not fit all with GI issues," Park says. "You need a diet and solutions that are individualized to you."