Key Takeaways
- Most people who react to “gluten” are not reacting to gluten. In controlled trials, only about 16 to 30% show symptoms triggered by gluten itself.
- FODMAPs are a more likely trigger. Wheat contains fructans, a type of FODMAP. In one controlled trial, fructans caused more symptoms than gluten did.
- Expectation matters. What you believe you’re eating can change how you feel.
- Get tested for celiac disease before you cut out gluten. Going gluten-free first can hide the result.
- The fix is a structured low FODMAP plan, followed by adding foods back one group at a time. The goal is a varied diet, not a permanent restriction.
What Gluten Sensitivity Actually Means
Doctors call it non-celiac gluten sensitivity (NCGS). People with NCGS get symptoms after eating gluten or wheat, but they don’t have celiac disease or a wheat allergy. A major review published in The Lancet on October 22, 2025, found that about 10% of adults worldwide say they have gluten or wheat sensitivity. The review also says that number overstates the true count.
There is no blood test or biomarker for NCGS yet. It’s a diagnosis of exclusion, which means doctors rule out other conditions first.
Is Gluten Low FODMAP?
No. Gluten is a protein, not a carbohydrate. The review defines gluten as the rubbery protein left after washing wheat dough. Wheat also contains fructans, which are FODMAPs. The Monash University FODMAP team lists wholemeal bread, rye bread, and wheat pasta among foods rich in fructans. See the Monash FODMAP food list for more information.
That’s why many people feel better on a gluten-free diet without gluten being the cause. Gluten comes with a lot of other food components. The review says many symptom improvements on gluten-free diets come from cutting FODMAPs, particularly fructans, which usually come along with gluten.
What Happens in Blinded Trials
In a blinded trial, neither the participant nor the researcher knows who gets gluten and who gets a placebo. That design is what makes the results trustworthy.
In controlled challenge studies, about 16 to 30% of people who self-report gluten sensitivity show symptoms triggered by gluten. That means most people react to something other than gluten.
Here is one example. In a 2013 study, 37 people with IBS and self-reported gluten sensitivity followed a low FODMAP diet for two weeks, and their symptoms improved. When they were then given gluten, whey protein, or a control, gluten-specific effects showed up in only 8% of participants.
The lead author, Jessica Biesiekierski of the University of Melbourne, put it this way: “Most people with NCGS aren’t reacting to gluten.” She and her team also argue that NCGS may be closer to IBS than to a distinct gluten disorder.
The Likely Culprits
FODMAPs. FODMAPs are short-chain carbohydrates that ferment in the gut and can cause bloating, gas, and pain. Fructans are the FODMAP that matters most in wheat.
A 2018 trial tested this directly. Fifty-nine people with self-reported gluten sensitivity ate three 7-day diets: one with gluten (5.7 grams a day), one with fructans (2.1 grams a day), and one placebo. Fructans caused more symptoms than gluten, and gluten did no better than placebo. The fructan came from chicory root and was given at a modest dose, so the researchers say more studies are needed.
Other wheat proteins. Amylase-trypsin inhibitors (ATIs) affect the immune system in lab and animal studies. The review notes that no controlled human trials have tested ATIs in people with NCGS. Treat them as a possible trigger, not a proven one.
Expectation. A 2024 trial of 83 people, most of them women, found that expectation played a large role. The review summarizes it this way: symptoms followed what people expected to eat more than the gluten they actually ate. That doesn’t mean the symptoms aren’t real. The brain and gut interact closely, and that interaction can amplify symptoms.
How to Test It the Right Way
Step 0: Rule out celiac disease first. Celiac testing only works if you’re eating gluten. The review says people should eat about 3 grams of gluten a day for 6 to 8 weeks before testing. Talk to your doctor before you change your diet.
Step 1: Try a low FODMAP approach. If celiac disease and wheat allergy are ruled out, the review suggests a gluten-free trial of about 4 to 6 weeks, ideally with FODMAP reduction. The Monash University low FODMAP program was developed for this purpose. It has three steps, and a dietitian can help you through it.
Step 2: Reintroduce FODMAPs one group at a time. The Monash app walks you through reintroduction and includes a diary for foods, symptoms, and stress. Stress matters here because the gut and brain influence each other.
Step 3: Keep what you tolerate. Most people end up with a diet that’s far less restricted than the one they started with.
The Monash app has the complete, current food list. The website has a sample list you can check in the meantime.
Gluten-Free Isn’t Automatically Healthy
Gluten-free products often contain less fiber and fewer vitamins and minerals than regular versions, and they usually cost more. Many people also drop other foods without a plan. The review warns that this can lead to nutrient gaps, and it recommends working with a dietitian.
Sourdough May Be Back on the Menu
The review notes that small portions of low-fructan wheat products, such as sourdough spelt, are used in practice. Monash also lists sourdough spelt bread as low FODMAP. Tolerance varies from person to person, so test it during your reintroduction phase.
What This Means for You
If you cut out gluten and still feel bad, the cause may be FODMAPs, other wheat components, or expectation. The right next step is a proper test, not a permanent diet.
Want help sorting out your triggers? Maybe you just want to talk about how to make sense of what you are going through. I am happy to talk with you, without putting pressure on you to buy a program from me. Learn more about True Wealth Health Coaching.
Frequently Asked Questions
Is gluten sensitivity real?
The symptoms are real. In controlled trials, though, gluten itself causes symptoms in only a minority of people who report sensitivity.
How do I tell if I have IBS or gluten sensitivity?
The two overlap a lot. The review says between 20% and 80% of people with suspected NCGS meet the criteria for IBS. Get celiac testing first, then work with a clinician on a structured elimination and reintroduction plan.
How do I know if I’m sensitive to FODMAPs?
Try a structured low FODMAP plan, then reintroduce one FODMAP group at a time while tracking your symptoms. If a group brings symptoms back, that group is a likely trigger for you.
What are the first signs of gluten intolerance?
Symptoms usually start within 2 to 6 hours of eating gluten or wheat. Bloating is the most common, along with abdominal pain, diarrhea, fatigue, and foggy thinking. DOI
Should I stay on a low FODMAP diet long term?
No. The program is meant to be temporary. Long-term restriction can leave gaps in your nutrition.
Can I eat sourdough?
Maybe. Monash lists sourdough spelt as low FODMAP. Test it yourself during reintroduction.
