You can eat
- Vegetables and fruit, fresh or frozen
- Legumes such as lentils, chickpeas, beans and peas
- Rice, corn, potatoes, sweet potatoes, quinoa and buckwheat—which, despite its name, is not wheat.
- Certified gluten-free oats, if you tolerate them.
- Fresh, unbreaded meat, fish, seafood and eggs
- Milk, plain yoghurt and cheese
- Plain nuts and seeds
- Extra virgin olive oil for cooking and dressing
What to avoid
- Bread, pasta, couscous, bulgur and flour made from wheat, spelt or kamut
- Barley and rye, including malt made from them
- Beer brewed with barley or wheat
- Battered and breaded foods, and sauces thickened with flour
- Pastries, biscuits and pizza made with wheat dough
- Packet soups and creams containing flour or pasta
Changes that help
Everyday bread
Instead of gluten-free sliced bread every day, try rice, potatoes or corn cakes, because many gluten-free products contain more fat and salt [6].
Whole grains
Instead of avoiding whole grains along with wheat, choose brown rice, buckwheat, quinoa or certified gluten-free oats (if you tolerate them), because fibre intake falls without whole grains [5].
Sweet treats
Instead of gluten-free biscuits or muffins, try fruit with plain yoghurt or a handful of nuts, because a “gluten-free” label does not make a sweet treat healthier.
Habits that help
- Eat slowly and chew well, because swallowing air can also cause gas and bloating.
- Look after your sleep and stress levels, as these can also affect how your gut responds.
This is one of the most common questions about food. Many people have already stopped eating bread on their own, feel somewhat better and do not know whether they have coeliac disease, are overreacting or have something else.
All three possibilities can be addressed. What changes is the order in which they are investigated, and that order matters.
Gluten intolerance, coeliac disease or wheat allergy?
What many people call gluten intolerance has a more precise name: non-coeliac gluten sensitivity. It involves digestive and other symptoms affecting different parts of the body that appear after eating gluten in people without coeliac disease or wheat allergy [2]. There is currently no test that can detect it [2].
It resembles two other conditions, and it is useful to distinguish them because they are managed differently.
- Coeliac disease. An autoimmune disease in which gluten damages the lining of the small intestine.
- Wheat allergy. The immune system reacts to wheat proteins, sometimes within minutes.
- Non-coeliac gluten sensitivity. Symptoms occur without coeliac antibodies or intestinal damage [2].
The symptoms overlap considerably. Bloating, gas, diarrhoea, stomach pain, tiredness or headaches can occur with all three. Symptoms alone therefore cannot tell you which one you have.
Why shouldn’t you stop eating gluten before testing?
Coeliac tests look for the effects gluten leaves in the body. European coeliac guidelines state that blood tests and biopsies should be done while gluten is still part of the diet [1]. If you have stopped eating it, antibody levels fall and the intestine heals. Tests may come back normal even if you have coeliac disease.
Testing usually starts with a blood antibody test requested by your doctor. If the result is abnormal, the usual confirmation is a duodenal biopsy—a sample from the first part of the small intestine—taken during a gastroscopy [4].
Stopping gluten too soon does not protect you; it leaves you without a diagnosis.
If you have already stopped and feel better, tell your doctor before eating it again. Repeating the tests requires eating gluten again for a while; your doctor will advise how much and for how long.
Wheat allergy is similar in this respect. If eating wheat causes an itchy mouth, hives or breathing difficulties, an allergy specialist should investigate before you change your diet.
What if gluten isn’t what makes you feel unwell?
Wheat contains more than gluten. It also contains fructans, sugars that the intestine does not absorb and that ferment in the colon. In a sensitive intestine, they can cause gas, bloating and pain. They are part of FODMAPs, the group of fermentable sugars reduced in the FODMAP diet.
A trial tested this in people who thought they were sensitive to gluten. Without knowing which was which, they ate one food containing gluten, another containing fructans and a third containing neither [3]. Symptoms occurred with fructans. Gluten caused no more discomfort than the control food [3].
This has a practical consequence. Fructans are also found in onions, garlic and some legumes. If fructans are the problem, stopping gluten only partly relieves symptoms. What helps is adjusting the amount of fructans you can tolerate, with professional support.
How it is confirmed, step by step
There is no laboratory test. Non-coeliac gluten sensitivity is confirmed by observing what happens when gluten is removed and then reintroduced [2]. An international group of experts proposed the following steps [2]:
- Rule out coeliac disease and wheat allergy while you are still eating gluten.
- Rate your main symptoms from 1 to 10 while eating as usual [2].
- Remove gluten for a few weeks, with a reviewed eating plan to ensure you still get everything you need.
- If you improve clearly, try gluten again under blinded conditions [2].
The blinded challenge helps prevent misleading results. For one week, you take 8 g of gluten or a control product each day without knowing which one [2]. You take a week off and then have the other product [2]. The challenge is considered positive if your symptoms change by at least 30% between the two weeks [2].
Outside a hospital or research study, this test is difficult to organise. More often, people follow an open, structured reintroduction, which is less reliable and therefore uses a symptom diary. In our consultations, we plan the elimination, diary and reintroduction, always based on the medical diagnosis already made.
What to eat if it is confirmed
The foundation is a gluten-free eating pattern that includes the usual food groups. The gluten-free diet explains how to plan everyday meals, read labels and replace wheat-based cereals.
There is a difference from coeliac disease that can make a big difference to daily life. With coeliac disease, even trace amounts matter, and a gluten-free diet is lifelong. It is unclear whether non-coeliac gluten sensitivity requires the same level of strictness. Many people tolerate small amounts; the aim is to find what works for you.
If fructans also affect you, the amount of garlic, onion or legumes is addressed too. That is why the plan is tailored to your symptoms and reviewed over time.
What you may lose by avoiding gluten without a reason
Avoiding gluten when you do not need to has costs. A study following thousands of adults without coeliac disease found no increase in coronary heart disease risk from eating gluten [5]. It did find that people who avoid gluten tend to eat fewer whole grains, which benefit heart health [5].
- Less fibre if wholemeal bread and pasta are not replaced with other wholegrain foods.
- More ultra-processed foods. Many gluten-free products are low in protein and higher in fat and salt [6].
- Higher costs because specialist gluten-free products often cost more.
There is another cost that does not show up on the receipt. Without a diagnosis, every meal away from home can become a question of what to order and how much risk to take.
Which mistakes do we see in consultations?
- Stopping gluten before blood tests. This is what most complicates diagnosis later.
- Trusting an intolerance test. IgG, hair and bioresonance tests do not diagnose gluten-related conditions.
- Replacing bread with gluten-free pastries. Your stomach may feel better, but your diet gets worse.
- Avoiding wheat while still eating lots of garlic and onion. If fructans are the issue, symptoms continue.
And the question we hear most often at the first appointment: “So am I gluten intolerant, or have I made it up?” Neither. The symptoms are real; what remains is finding out where they come from.
The full guide, including allergies and intolerances to lactose or fructose, is in our guide to food allergies and intolerances.
The Federation of Coeliac Associations of Spain explains step by step how coeliac disease is diagnosed.
If coeliac disease has been ruled out and you are unsure what to remove or how much gluten you tolerate, we can work through it with you. Our team of dietitians specialising in allergies and intolerances can guide you through elimination and reintroduction with your medical diagnosis in mind, in Barcelona and online.
Your first step this week
Start a diary without changing what you eat
For two weeks, write down what you eat, which symptoms you notice and how bothersome they are from 1 to 10. Take it to your doctor and dietitian.
Your 7-day menu, ready for the fridge
- 7-day menu with the shopping list
- Easy recipes to cook at home
- Written by dietitian-nutritionists
Where should we send it?
Free PDF, in your inbox in a moment.
Data controller: Alimmenta Tu Vida, S.L. Purpose: to send you the guide and, only if you tick the second box, tips by email on the topic. You can withdraw your consent and exercise your rights at [email protected]. Legal basis, recipients and retention periods are in our privacy policy.
When to see a doctor
When should you see a doctor?
We can help you remove and reintroduce gluten in an organised way and make sure you still get everything you need in the meantime. Diagnosing coeliac disease or wheat allergy and ordering tests are your doctor’s responsibility.
Arrange a medical appointment without waiting to change your diet if you notice any of these signs:
- Diarrhoea lasting weeks, weight loss and anaemia that does not improve with iron [7].
- In a child: they stop gaining weight or growing, or puberty is delayed [7].
- You have a first-degree relative with coeliac disease and digestive symptoms [7].
- You have been eating completely gluten-free for some time and symptoms return or do not go away [7].
If you do not yet have a diagnosis, book an appointment with your GP this week (or your child’s paediatrician) and do not stop eating gluten until they advise you to. If you have coeliac disease and symptoms return or persist, continue eating gluten-free and book an appointment with your doctor this week. Once the diagnosis is confirmed, follow-up is with your gastroenterologist and a dietitian.
Most people who feel unwell after eating gluten do not have anything serious. Finding out what is happening is what lets you eat with confidence again.
Tell us your diagnosis and we will tell you what can be brought back
We review your report and everything you have stopped eating, and you leave knowing what to avoid and what not to. Bring any labels you are unsure about. Your eating plan, with alternatives for what you avoid, arrives a week later.
Keep reading
Gluten-free diet: coeliac disease, gluten sensitivity and what to eat
Does bread make you feel bloated, have you heard about coeliac disease, or are you wondering whether you…
FODMAP diet: what to eat, what to avoid and how long it lasts
You have been told to follow a low-FODMAP diet and all you find are lists of hundreds of…
Food allergies and intolerances: what they are and how they differ
A food disagrees with you and you do not know whether it is an allergy, an intolerance or…
Gluten-free bread: how to choose it and what to check on the label
Several gluten-free loaves look much the same. The question comes when you turn the pack over: which one…
Weekly gluten-free menu: seven days, breakfast and shopping list
With the diagnosis in hand, the question is what to put on the plate on Monday without living…
Migraine and DAO deficiency: what the evidence says
You have recurring migraine attacks and have read that an enzyme that is not working is to blame.…
ConsultationDietitian-nutritionist for allergies and intolerances in Barcelona and online
With your diagnosis in front of us, we help you eat a varied diet safely. Without cutting out…
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Sources
- Al-Toma A, Volta U, Auricchio R, et al. European Society for the Study of Coeliac Disease (ESsCD) guideline for coeliac disease and other gluten-related disorders. United European Gastroenterol J. 2019;7(5):583-613. doi:10.1177/2050640619844125
- Catassi C, Elli L, Bonaz B, et al. Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts’ Criteria. Nutrients. 2015;7(6):4966-77. doi:10.3390/nu7064966
- Skodje GI, Sarna VK, Minelle IH, et al. Fructan, rather than gluten, induces symptoms in patients with self-reported non-celiac gluten sensitivity. Gastroenterology. 2018;154(3):529-539.e2. doi:10.1053/j.gastro.2017.10.040
- Rubio-Tapia A, Hill ID, Semrad C, et al. American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease. Am J Gastroenterol. 2023;118(1):59-76. doi:10.14309/ajg.0000000000002075
- Lebwohl B, Cao Y, Zong G, et al. Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study. BMJ. 2017;357:j1892. doi:10.1136/bmj.j1892
- Melini V, Melini F. Gluten-Free Diet: Gaps and Needs for a Healthier Diet. Nutrients. 2019;11(1):170. doi:10.3390/nu11010170
- Husby S, Koletzko S, Korponay-Szabó I, et al. European Society Paediatric Gastroenterology, Hepatology and Nutrition Guidelines for Diagnosing Coeliac Disease 2020. J Pediatr Gastroenterol Nutr. 2020;70(1):141-156. doi:10.1097/MPG.0000000000002497
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