Do You Actually Have Gluten Sensitivity?

A new study suggests your stomach issues might not be caused by gluten.

It’s easy to blame gluten if you feel sick after eating lots of bread and pasta. In fact, one in 10 people around the world believe gluten causes symptoms such as bloating, diarrhea, and fatigue.

Gluten has become such a health villain that the gluten-free products market is expected to reach a whopping $11.48 billion in the US by 2029.

But unless you have celiac disease (hello, raises hand) or a wheat allergy—gluten, the protein in wheat, barley, and rye—might not actually be what’s making you feel sick.

As I reported earlier this year in National Geographic and in this newsletter, gluten tends to get a bad rap unnecessarily.

The anti-gluten narrative has gotten so strong that even though I have celiac disease and must avoid gluten at all costs, I still feel compelled to defend it against all the unwarranted negative claims.

Now, a new study published in The Lancet validates what many experts I’ve chatted with have been talking about for years: Most people who think they’re gluten sensitive probably don’t have a problem with gluten after all.

I interviewed lead study author Jessica Biesiekierski, PhD, associate professor and head of human nutrition at The University of Melbourne, via email, about how her team conducted the study and what they found.

Table of contents:

• Breaking down the new gluten sensitivity study

• Why you may feel sick after eating bread

• What to do if you think you might be gluten sensitive

• The bottom line on gluten sensitivity

Breaking down the new gluten sensitivity study

Biesiekierski’s team of researchers wanted to answer a simple but controversial question: Is gluten really the problem for people who feel unwell after eating bread or pasta?

“Millions now avoid gluten, yet the science has been inconsistent,” she says.

The study specifically looked at the research around “non-celiac gluten sensitivity (NCGS),” which refers to people who feel sick after eating gluten but don’t have celiac disease or a wheat allergy.

As the study authors note, there’s a lot of uncertainty in the medical community about whether NCGS is a distinct gluten disorder.

For the study, the researchers pulled together every placebo-controlled gluten-challenge study published—this included over 18 double-blind trials as well as over 40 mechanistic studies looking at the immune system, the gut lining, the microbiome, and the gut-brain connection.

“We analyzed them as one body of evidence to understand what’s actually causing symptoms in people who believe they’re ‘gluten sensitive,” says Biesiekierski.

What they found: “In study after study, gluten reactions were rare and usually small, and many people who were convinced gluten made them unwell reacted just as strongly to placebo,” explains Biesiekierski.

Meta-analyses showed only 16%–30% of people with self-reported gluten sensitivity actually have symptoms triggered by gluten.

These findings didn’t totally surprise Biesiekierski. “I’ve been seeing hints of this pattern for years,” she says. “But what did surprise me was just how consistent the evidence has been across two decades of research.”

When you look at all the blinded trials together, she says, “the lack of a clear gluten-specific response is remarkably consistent.”

“In study after study, gluten reactions were rare and usually small, and many people who were convinced gluten made them unwell reacted just as strongly to placebo.” - Jessica Biesiekierski, PhD, lead study author

Why you may feel sick after eating bread

So, if gluten isn’t to blame, what is? Well, it turns out there are a couple of things going on here.

For starters, Biesiekierski’s team confirmed symptoms are largely caused by FODMAPs—short-chain carbohydrates that are poorly absorbed in the small intestine—rather than gluten.

FODMAPs (which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols) are fermented by gut bacteria when they reach the large intestine, producing gas and drawing in water, explains Biesiekierski.

For people with a sensitive gut—especially those with irritable bowel syndrome (IBS)—this can lead to bloating, abdominal pain, or changes in bowel movements, she says.

“Symptoms frequently improved when FODMAPs were reduced, even when gluten was added back in,” notes Biesiekierski.

It’s easy to understand why you’d default to thinking gluten is responsible for your GI woes, though.

Gluten-based products like bread, pasta, and cereal are high in FODMAPs—and when you go gluten-free, that often means removing a lot of high-FODMAP foods from your diet, says Biesiekierski.

The gut-brain connection is also at play.

Similar to what doctors see in IBS patients, the researchers found that in people with NCGS, the digestive system becomes more sensitive, causing the brain to interpret normal gut signals as discomfort, explains Biesiekierski.

NCGS is therefore more like conditions such as IBS (a gut-brain disorder) than a true gluten disorder, according to a press release from the study authors.

What to do if you think you might be gluten sensitive

First things first: If you’re having symptoms and you think they may be related to gluten, don’t go gluten-free on your own.

“See a doctor to rule out celiac disease and wheat allergy before removing gluten—otherwise, the tests won’t be accurate,” says Biesiekierski.

If the tests come back negative, you should make an appointment with a registered dietitian. They “can guide a structured approach to figure out what’s actually driving symptoms,” says Biesiekierski.

A low-FODMAP diet is usually pretty effective in cases like this. “It temporarily reduces foods that are commonly fermented in the gut—things like wheat products, certain fruits and vegetables, onions, garlic, beans, and some dairy,” says Biesiekierski.

It’s important to note that a low-FODMAP diet isn’t meant to be long-term. “After a short restriction phase, foods are reintroduced to identify personal triggers and broaden the diet again,” says Biesiekierski.

The bottom line on gluten sensitivity

As Biesiekierski points out, “avoiding gluten when you don’t need to can be expensive, socially limiting, and nutritionally imbalanced.”

Gluten-free products are, on average, 139% more expensive in the US and often lower in fiber and micronutrients.

That’s why it’s a good idea to get checked out by a doctor first to see if you have celiac disease or a wheat allergy—and if you don’t, you should work with a dietitian to pinpoint what else could be bothering you.

Biesiekierski also wants you to know this: Recognizing that something other than gluten is causing your GI symptoms doesn’t minimize your experience.

“It actually opens the door to treatments that are more personalized and effective than long-term food avoidance,” she says.

To that end, her team is running the world’s first fully online IBS clinical trial, comparing two evidence-based treatments: the low-FODMAP diet and an exposure-based therapy that retrains the gut-brain connection. If you live in the US, you can find out more and join the trial here.

Finally, as someone living with celiac disease, I think it’s important to highlight that all this confusion around “gluten sensitivity” can be seriously harmful to celiacs.

For example, I often see gluten-sensitive folks online claiming they can eat regular sourdough bread because it’s lower in gluten, when in reality it’s lower in FODMAPs.

Many celiacs read these posts and think they can do the same—not realizing the person sharing this advice doesn’t actually have a diagnosed gluten-related disorder.

Being as accurate as possible helps protect people who truly need to avoid gluten 100% of the time. I hope this study clears up confusion and dispels rampant misinformation about gluten.

What are your thoughts on this new study? Drop a comment and let me know!

Sources:

• Jessica Biesiekierski, PhD, associate professor and head of human nutrition at The University of Melbourne

• Gut. “Global prevalence of self-reported non-coeliac gluten and wheat sensitivity: a systematic review and meta-analysis.” 28 October 2025. https://gut.bmj.com/content/early/2025/10/13/gutjnl-2025-336304

• MarketsandMarkets. Gluten-Free Products Market Size, Trends & Forecast 2029. https://www.marketsandmarkets.com/Market-Reports/gluten-free-products-market-738.html

• Celiac Disease Foundation. What is Celiac Disease? https://celiac.org/about-celiac-disease/what-is-celiac-disease/

• Mayo Clinic. Wheat allergy. https://www.mayoclinic.org/diseases-conditions/wheat-allergy/symptoms-causes/syc-20378897

• National Geographic. Is gluten really that bad for you? Here’s what happens when you stop eating gluten. https://www.nationalgeographic.com/science/article/gluten-free-diet-health-effects

• The Lancet. Non-coeliac gluten sensitivity. Volume 406, Issue 10518, 22–28 November 2025. https://www.sciencedirect.com/science/article/abs/pii/S0140673625015338

• Beyond Celiac. What is Gluten Sensitivity? https://www.beyondceliac.org/celiac-disease/related-conditions/ncgs/

• Monash University. FODMAPs and Irritable Bowel Syndrome. https://www.monashfodmap.com/about-fodmap-and-ibs/

• Mayo Clinic. Irritable bowel syndrome. https://www.mayoclinic.org/diseases-conditions/irritable-bowel-syndrome/symptoms-causes/syc-20360016

• The University of Melbourne. Gluten sensitivity: It’s not actually about gluten. https://www.unimelb.edu.au/newsroom/news/2025/october/gluten-sensitivity-its-not-actually-about-gluten

• Nutrients. “Persistent Economic Burden of the Gluten Free Diet.” 14 February 2019. https://celiacdiseasecenter.columbia.edu/wp-content/uploads/2019/07/2019-Persistent-Economic-Burden-of-the-Gluten-Free-Diet.pdf

• Springer Nature. “Gluten-free Diet, a Friend or a Foe, an American Perspective.” Volume 80, article number 8, (2025). https://link.springer.com/journal/11130

• Monash University. Sourdough processing & FODMAPs. https://www.monashfodmap.com/blog/sourdough-processing-fodmaps/