Crohn's and IBD: A Food-by-Food UK Guide

Inflammatory bowel disease is not the same as irritable bowel syndrome. This distinction matters, because the dietary approaches are different, the consequences of getting it wrong are different, and the emotional toll of living with IBD is in a category of its own.

Crohn's disease and ulcerative colitis, the two main forms of IBD, involve chronic inflammation of the digestive tract. Crohn's can affect any part of the tract from mouth to anus. Ulcerative colitis affects the colon and rectum. Both involve periods of flare (active inflammation with severe symptoms) and remission (reduced or absent symptoms).

Roughly 500,000 people in the UK live with IBD. That number has been rising for decades, particularly in younger adults. The condition is not caused by diet. It is an autoimmune condition with genetic, environmental, and immunological components. But diet profoundly affects symptoms, nutritional status, and quality of life.

The frustration for people with IBD is that dietary advice is sparse, contradictory, and often boils down to "avoid anything that bothers you." That is technically true but practically useless when everything seems to bother you during a flare.

Flare versus remission: two different diets

This is the most important distinction in IBD nutrition, and it is rarely explained clearly enough.

During a flare, the lining of your gut is actively inflamed, sometimes ulcerated. Your ability to digest and absorb food is compromised. Fibre, which is normally beneficial, can irritate inflamed tissue and worsen symptoms. The goal during a flare is to reduce the mechanical and chemical load on your gut while maintaining adequate nutrition.

During remission, the inflammation has subsided. Your gut can handle a broader range of foods. The goal shifts to maintaining nutritional adequacy, supporting gut healing, and potentially reducing the frequency of future flares through diet quality.

A food that is excellent during remission (a bowl of lentil soup, rich in fibre and plant protein) can be genuinely harmful during a flare (indigestible fibre scraping against inflamed mucosa). This is why blanket food lists for IBD are problematic. Context matters enormously.

Eating during a flare

When symptoms are active, the priority is gentle, easily digestible, nutrient-dense food.

Proteins that work: Well-cooked chicken breast (shredded or diced small), white fish (cod, haddock, plaice, steamed or poached), eggs (scrambled or poached, not fried), smooth nut butters, and well-cooked tofu. Protein needs actually increase during a flare because inflammation increases protein turnover and losses from the gut.

Carbohydrates that work: White rice, white pasta, white bread, mashed potato (without skin), porridge (made smooth), and ripe bananas. These are low in insoluble fibre, which reduces mechanical irritation. This is one of the few clinical contexts where refined carbohydrates are the medically correct choice.

Vegetables that work (cooked and soft): Peeled and well-cooked carrots, butternut squash, courgettes (peeled and deseeded), sweet potato (peeled and mashed). Avoid raw vegetables, salads, skins, seeds, and anything with tough or fibrous texture during active inflammation.

Fruits that work: Ripe bananas, peeled and stewed apples, tinned peaches or pears in juice (not syrup), melon. Avoid raw fruits with skin, berries with seeds, citrus fruits, and dried fruit.

What to avoid during a flare: High-fibre foods (wholegrains, raw vegetables, legumes, nuts, seeds), spicy foods, fatty or fried foods, alcohol, caffeine, and dairy (many people with IBD develop secondary lactose intolerance during flares due to damaged intestinal villi). Carbonated drinks can worsen bloating.

Oral nutritional supplements. During severe flares, normal food intake may be insufficient. Your IBD team may recommend oral nutritional supplement drinks (such as Ensure or Fortisip) to maintain calorie and nutrient intake. In some cases, exclusive enteral nutrition (a liquid diet) is used therapeutically, particularly in Crohn's disease. This is a medical intervention that should only be undertaken under specialist supervision.

Eating during remission

When inflammation has settled, you can gradually reintroduce a wider range of foods. The goal is to eat as broadly and nutritiously as possible while identifying your personal triggers.

Reintroduce fibre gradually. Fibre supports gut microbiome diversity, which is often depleted in IBD. But reintroduce it slowly. Start with soluble fibre sources (oats, peeled fruits, well-cooked vegetables) before adding insoluble fibre (wholegrains, raw vegetables, skins, seeds). Too much too fast can provoke symptoms even in remission.

Prioritise omega-3. Oily fish (salmon, sardines, mackerel) provide EPA and DHA, which have anti-inflammatory properties. The evidence for omega-3 in IBD specifically is mixed, but the general anti-inflammatory benefit is well established and there is no downside to including it.

Include fermented foods cautiously. Natural yoghurt and kefir may support gut microbiome recovery. However, fermented foods that are also high in histamine (aged cheese, sauerkraut, kimchi, wine) can trigger symptoms in some IBD patients. Start with plain, fresh fermented dairy and observe your response.

Maintain protein intake. Even in remission, protein requirements remain elevated compared to the general population, because your gut is still healing and remodelling. Aim for at least 1.0-1.2g per kilogram of body weight.

Monitor micronutrients. IBD patients are at elevated risk for deficiencies in iron (blood loss from inflamed gut), B12 (particularly if the terminal ileum is affected, as in many Crohn's patients), folate, vitamin D, zinc, and calcium. Your IBD team should check these regularly.

The trigger identification challenge

IBD triggers are highly individual. Two people with Crohn's disease can have completely different trigger foods. This makes universal food lists frustrating, because a food that is perfectly safe for one person causes a flare in another.

The most reliable approach is a structured food and symptom diary, ideally maintained during stable remission so you are identifying true dietary triggers rather than foods that happened to coincide with a flare caused by something else entirely.

Common reported triggers (though these vary widely between individuals): alcohol, caffeine, spicy foods, high-fat foods, raw vegetables, sweetcorn, popcorn, seeds, nuts, and in some people, specific FODMAPs (particularly fructans from wheat and onions, and lactose from dairy).

The FODMAP approach can be useful for IBD patients, but should be undertaken with dietitian guidance. The FODMAP restriction was developed for IBS, and IBD has additional considerations (nutrient malabsorption risk, medication interactions, need for higher protein and calorie intake) that a standard FODMAP protocol does not account for.

How MyFoodFit scores for Crohn's and IBD

The Crohn's/IBD profile applies constraints that reflect the specific nutritional reality of living with inflammatory bowel disease.

High-fibre foods, which receive positive modifiers for most profiles, are treated differently. The scoring does not penalise fibre during remission (where it is beneficial), but the constraint engine flags very high-fibre products as potentially problematic, reflecting the need for caution.

Processed meat receives a dedicated penalty, reflecting research linking processed meat consumption to increased IBD flare risk.

Omega-3 rich foods receive a positive modifier, reflecting the anti-inflammatory benefit.

The allergen engine handles the secondary food intolerances common in IBD. If you have IBD and have developed lactose intolerance, adding the dairy allergy profile catches lactose-containing products.

As with all medical profiles, a disclaimer badge is always displayed, because IBD dietary management should be supervised by your gastroenterologist and an IBD-specialist dietitian.

Getting support

Crohn's and Colitis UK (crohnsandcolitis.org.uk) is the main UK charity supporting people with IBD. They provide dietary guides, helpline support, and local group networks. Their information is reliable, evidence-based, and free.

Your IBD team should include a specialist dietitian. If you have not been referred to one, ask your gastroenterologist. The dietary management of IBD is too complex and too individual to navigate without professional support, particularly during flares and in the period immediately after diagnosis.

What a food scoring app can provide is day-to-day decision support between clinic appointments. It cannot replace your IBD dietitian, but it can make the supermarket less overwhelming.

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This content is for information only and does not replace medical advice. IBD is a serious condition requiring specialist management. Always follow the guidance of your gastroenterologist and IBD dietitian.