At a glance
- Large studies link eating a lot of ultra-processed food with a higher chance of getting Crohn's disease. A link is not proof that the food causes it.
- Food is not a replacement for your IBD medicine. Keep taking it as prescribed.
- Cook more meals from whole foods, like vegetables, fruit, beans, whole grains, eggs, fish and plain meat.
- You don't need to be perfect. Swap one or two packaged foods a week for home-made ones.
- If you want to cut back on emulsifiers, check ingredient lists for carboxymethylcellulose (cellulose gum), polysorbate 80 and carrageenan.
- Don't cut out whole food groups on your own. Ask for a dietitian if you are losing weight or avoiding many foods.
Many people with IBD ask, “Did my diet cause this?” and “What should I eat now?” This guide explains what we know about ultra-processed foods, what we don’t know yet, and some easy steps you can try.
What are ultra-processed foods?
Almost all food is processed in some way. Washing, freezing and cooking are all kinds of processing. Researchers often sort food into four groups. This system is called NOVA.
| Group | Examples |
|---|---|
| 1. Whole or lightly processed: food close to how it grows | Fresh or frozen vegetables and fruit, plain milk, eggs, dried beans, rice, oats, plain meat and fish |
| 2. Cooking ingredients | Oil, butter, sugar, salt |
| 3. Processed foods: group 1 foods with salt, sugar or oil added | Canned vegetables, cheese, fresh bread, salted nuts |
| 4. Ultra-processed foods: factory-made, with things you would not use at home | Pop, chips, candy, packaged cookies, many breakfast cereals, hot dogs, chicken nuggets, instant noodles |
A food is likely ultra-processed if its ingredient list has things you would not find in a home kitchen. Examples are colours, flavours, sweeteners, thickeners and emulsifiers. Emulsifiers help oil and water stay mixed. They make foods smooth and help them last longer.
Canada’s Food Guide uses a slightly different idea, “highly processed foods.” It means foods that add a lot of salt, sugar or saturated fat. Its advice is to eat them less often and in small amounts.
Since 2026, many packaged foods in Canada show a black and white “High in” symbol on the front. It tells you if a food is high in saturated fat, sugars or sodium (salt). This symbol is not the same as “ultra-processed.” Still, it is a quick way to spot many highly processed foods.
What do large studies show?
Several large studies followed healthy adults for many years. They asked what people ate. Then they counted who was later diagnosed with IBD.
- The PURE study followed over 116,000 adults in 21 countries for about 10 years. People who ate 5 or more servings of ultra-processed food a day were about 1.8 times as likely to be diagnosed with IBD as people who ate less than 1 serving a day.
- When five large studies were combined, with over 1 million people, the link was clear for Crohn’s disease. People who ate the most ultra-processed food were about 1.7 times as likely to get Crohn’s.
- For ulcerative colitis (UC), the link was weak or not there at all.
It helps to keep the numbers in perspective. IBD was rare in the PURE study.
About 1.8 times
But only about 4 in 1,000
What about additives like emulsifiers?
Some scientists think certain food additives might upset the gut. Most of the early research was done in mice.
- In mice, two emulsifiers, carboxymethylcellulose and polysorbate 80, caused gut inflammation. This was a lab study. Mice are not people.
- In healthy people, a small study gave 16 adults a carefully controlled diet for 11 days. Some of them also got a large daily dose of carboxymethylcellulose. Their gut bacteria became less varied. The dose was likely more than most people eat, and no one developed IBD.
- In people with Crohn’s disease, a UK trial called ADDapt tested a low-emulsifier diet for 8 weeks in 154 adults with mild to moderate Crohn’s. Symptoms improved in about 49 out of 100 people on the low-emulsifier diet, compared with 31 out of 100 in the other group. These results were shared at a meeting in 2025. They have not yet been published as a full, checked paper.
- A smaller trial in Australia gave 24 people with active Crohn’s a diet high or low in emulsifiers for 4 weeks. It found no real difference.
So the answer is not settled. Experts who study IBD and diet say it “may be prudent,” or sensible, to cut back on foods with these additives. They also say the proof is weak.
What about titanium dioxide?
Titanium dioxide is a white colouring. It is no longer allowed in food in the European Union. Health Canada reviewed the research in 2022. It found no clear proof that it harms people, and it is still allowed in Canada. Some IBD experts suggest eating less of it, but the evidence is weak.
What we don’t know yet
- Whether eating less ultra-processed food changes how IBD behaves once you have it.
- Which foods or additives matter most, if any.
- How much is “too much.” No safe or unsafe amount has been found.
- Whether a low-emulsifier diet helps ulcerative colitis. The ADDapt trial only included Crohn’s.
European IBD experts said in 2025 that it is sensible to limit ultra-processed foods as part of healthy eating. They also said that avoiding them completely is not needed and is usually not realistic.
Simple steps you can take
You don’t need a strict diet. Small changes count. Choose what works for your budget and your life.
Cook more from whole foods
Build meals around vegetables, fruit, beans, lentils, whole grains, eggs, fish, chicken and plain meat. Frozen and canned vegetables and fruit are fine choices.Read the ingredient list, if you want to limit emulsifiers
Look for carboxymethylcellulose (also called cellulose gum), polysorbate 80 and carrageenan. They are common in some ice creams, creamy sauces, dressings, desserts and processed meats.Make one swap at a time
Start with one of the swaps below. When it feels easy, try another.
- Instead of A sugary cereal, try Oatmeal
- Instead of A frozen meal, try A home-made sandwich
- Instead of A ready meal on a busy day, try Home-made leftovers (cook extra and freeze it)
- Instead of Pop or energy drinks, try Water, milk, or plain tea or coffee
Don’t cut out too much
People with IBD are more likely to lose weight or miss out on nutrients. Cutting out many foods can make this worse. Crohn’s and Colitis Canada advises against avoiding whole food groups for a long time unless a dietitian is helping you.
Ask your IBD team for a dietitian if you:
- are losing weight without trying
- are avoiding many foods because you are afraid of symptoms
- feel stressed or anxious about eating
- have a narrowing (stricture) in your bowel, since some whole foods may need to be cooked soft or avoided
Did my diet cause my IBD?
Almost certainly not on its own. IBD comes from a mix of genes, the immune system, gut bacteria and things around us. Diet may be one small piece of that. Nothing you ate means this is your fault.
Should my children avoid ultra-processed food to prevent IBD?
We don’t know if this would prevent IBD. Healthy eating with mostly whole foods is good for every family anyway. Canada’s Food Guide is a good place to start.
Sources for this guide
Sources
- Monteiro CA, et al. Ultra-processed foods: what they are and how to identify them. Public Health Nutr 2019;22:936–41. PMID 30744710 The NOVA groups and the definition of ultra-processed food used in this guide
- Health Canada. Canada's Food Guide: Limit highly processed foods (2026). Canadian advice to eat highly processed foods less often and in small amounts (page modified 2026-05-04)
- Health Canada. Nutrition labelling: front-of-package nutrition symbol (modified August 2026). Black-and-white magnifying-glass 'High in' symbol for saturated fat, sugars and/or sodium; mandatory on prepackaged foods at or above set levels (industry deadline January 1, 2026); plain milk, plain yogurt, cheese and plain fruit and vegetables are exempt
- Narula N, et al. Association of ultra-processed food intake with risk of inflammatory bowel disease: prospective cohort study (PURE). BMJ 2021;374:n1554. PMID 34261638 116,087 adults, 21 countries, median 9.7 years, 467 new IBD cases. 5+ servings a day vs under 1: HR 1.82 (1.22–2.72); 1–4 servings: HR 1.67 (1.18–2.37)
- Narula N, et al. Food processing and risk of inflammatory bowel disease: a systematic review and meta-analysis. Clin Gastroenterol Hepatol 2023;21:2483–95. PMID 36731590 5 cohorts, over 1 million people. Crohn's HR 1.71 (1.37–2.14); ulcerative colitis HR 1.17 (0.86–1.61), not significant
- Chen J, et al. Intake of ultra-processed foods is associated with an increased risk of Crohn's disease (UK Biobank). J Crohns Colitis 2023;17:535–52. PMID 36305857 Crohn's HR 2.00 (1.32–3.03); no link with ulcerative colitis
- Lo CH, et al. Ultra-processed foods and risk of Crohn's disease and ulcerative colitis: a prospective cohort study. Clin Gastroenterol Hepatol 2022;20:e1323–37. PMID 34461300 Crohn's HR 1.70 (1.23–2.35) highest vs lowest quarter; no consistent link with ulcerative colitis
- Chassaing B, et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature 2015;519:92–6. PMID 25731162 Mouse study: carboxymethylcellulose and polysorbate 80 caused gut inflammation in mice
- Chassaing B, et al. Randomized controlled-feeding study of dietary emulsifier carboxymethylcellulose reveals detrimental impacts on the gut microbiota and metabolome. Gastroenterology 2022;162:743–56. PMID 34774538 16 healthy adults, 11 days, 15 g a day of CMC (more than most people eat): less diverse gut bacteria and fewer short-chain fatty acids
- Bancil A, et al. Emulsifier restriction is an effective therapy for active Crohn's disease: the ADDapt trial. J Crohns Colitis 2025;19(Suppl 1):i262 (conference abstract). 154 adults with mild to moderate active Crohn's, 8 weeks. Symptom response 49.4% low-emulsifier vs 30.7% control (p=0.019). Not yet published as a full paper (PubMed and web search checked 11 October 2026)
- Fitzpatrick JA, et al. Clinical trial: the effects of emulsifiers in the food supply on disease activity in Crohn's disease. Aliment Pharmacol Ther 2025;61:1276–89. PMID 39967287 24 people with active Crohn's, 4 weeks: no significant difference between high- and low-emulsifier diets
- Levine A, et al. Dietary guidance from the International Organization for the Study of Inflammatory Bowel Diseases. Clin Gastroenterol Hepatol 2020;18:1381–92. PMID 32068150 'It may be prudent' to reduce processed foods with carrageenan, carboxymethylcellulose and polysorbate 80 (very low evidence)
- Svolos V, et al. European Crohn's and Colitis Organisation consensus on dietary management of inflammatory bowel disease. J Crohns Colitis 2025;19:jjaf122. PMID 40650933 Statement 47: UPF linked with developing Crohn's but not UC; limit UPF as part of healthy eating; complete avoidance cannot be recommended
- Hashash JG, et al. AGA clinical practice update on diet and nutritional therapies in patients with IBD. Gastroenterology 2024;166:521–32. PMID 38276922 Mediterranean-style diet low in ultra-processed foods for general health; no diet has consistently lowered flare rates
- Health Canada. Titanium dioxide (TiO2) as a food additive: current science report. No conclusive evidence that food-grade titanium dioxide is a concern for human health; still permitted in Canada
- Crohn's and Colitis Canada. Eating and drinking with IBD. Limit refined sugars, sweets and processed foods; don't avoid food groups for long periods without a dietitian
This guide is for general education. It can't replace advice from your own care team, who know your health history.