Crohn's Diet: Exclusion Diets, Disease Flares and Trials

No single Crohn's disease diet has been shown to stop flares. The American Gastroenterological Association (AGA) advises a Mediterranean-style pattern for people with inflammatory bowel disease (IBD), and the NIDDK says researchers have not found that specific foods cause or worsen Crohn's symptoms^[1][2]. The best-tested diet treatment is the Crohn's disease exclusion diet (CDED) with partial formula feeding, which has trial support for mild-to-moderate disease, mostly in children^[3][4].

This guide covers the exclusion diets, how to eat during a flare and in remission, which foods are worth limiting, and the nutrient gaps to watch. Diet supports medical care and does not replace it. For symptoms, causes and treatment, see our page on Crohn's disease.

Get medical help promptly if you have severe or worsening belly pain, repeated vomiting, blood in your stool, fever, or unintended weight loss. These can signal a flare or a complication such as an intestinal blockage, and they need a clinician, not diet changes^[5][6][7].

What does the evidence say about a Crohn's diet?

The evidence supports a few practical points and leaves many food-by-food questions open.

• Mediterranean-style eating is the default advice. The AGA 2024 update recommends that all people with IBD, unless contraindicated, follow a diet rich in fruits, vegetables, monounsaturated fats, complex carbohydrates and lean protein, and low in ultra-processed foods, added sugar and salt^[1].
• No diet has reliably prevented flares. The same update says no diet has consistently reduced flare rates in adults with IBD. A diet low in red and processed meat may reduce ulcerative colitis flares but has not been found to reduce relapse in Crohn's^[1].
• Food triggers are individual. The NIDDK suggests a food diary to spot foods that seem to worsen your symptoms^[2].
• Medicine remains first-line. A 2024 Lancet review describes diet as something that may be combined with advanced therapies, not a substitute for them^[8].

The exact cause of Crohn's disease is unknown, and the inflammation is patchy and can affect any part of the gut^[8][7]. That is one reason a single diet is unlikely to suit everyone. ESPEN's 2023 guideline update, written for clinicians, runs to 71 recommendations and adds a chapter on microbiota modulation^[9].

What is the Crohn's exclusion diet (CDED)?

CDED is a structured whole-food diet that removes foods thought to harm the gut microbiota and intestinal barrier, usually paired with partial formula feeding^[10]. A systematic review describes the usual design^[4]:

• Phases: two to three, changing about every 6 weeks (weeks 1 to 6, weeks 7 to 12, then maintenance).
• Required foods: fresh whole foods such as chicken, eggs, potatoes and rice, plus fruit and vegetables as sources of resistant starch and pectin.
• Excluded foods: processed foods, emulsifiers, animal fat, red and processed meat, carrageenan, gluten and dairy.
• Partial enteral nutrition (PEN): a polymeric formula covering about 50% of energy in phase 1 and about 25% afterwards.

CDED is not a diet to start from a blog post. The AGA says people on it warrant co-management with a registered dietitian^[1].

What did the exclusion diet trials find?

In trials of mild-to-moderate disease, remission rates on CDED ranged from about 55% to 82% depending on the population and timepoint, but the studies are small and several were open-label^[4].

Two cautions apply. The adult trials were open-label and small, and the Yanai pilot was funded in part by Nestlé Health Science, which makes enteral formulas^[11]. The 2023 systematic review of seven studies concluded CDED "seemed" effective but flagged heterogeneity and a need for larger randomized trials^[4]. A 2023 expert review calls it an established dietary therapy and a possible alternative to exclusive enteral nutrition, especially in mild-to-moderate disease^[10].

What is exclusive enteral nutrition, and who uses it?

Exclusive enteral nutrition (EEN) means getting nearly all calories from a liquid formula for several weeks. The AGA says it is effective for inducing remission and endoscopic response in Crohn's, with stronger evidence in children than adults, and that it may serve as a steroid-sparing bridge^[1]. It is also suggested for malnourished patients before elective surgery to improve nutrition and reduce complications^[1]. A UK hospital patient page says a dietitian may use it for about 10 days to 8 weeks during a flare, with monitoring^[7].

Is a Mediterranean or specific carbohydrate diet better for Crohn's?

Neither beat the other in the one large adult trial. In 191 adults with mild-to-moderate Crohn's, symptomatic remission at week 6 was 46.5% on the Specific Carbohydrate Diet (SCD) and 43.5% on a Mediterranean-style diet (P = .77)^[14]. The authors suggested the Mediterranean diet may be preferred for most patients because it is easier to follow and has other health benefits^[14]. A 2024 umbrella review also linked Mediterranean, vegetarian and SCD patterns to lower IBD incidence or progression^[15].

What should you eat with Crohn's during a flare?

During a flare, the goal is enough calories and protein, because inflammation reduces absorption and appetite. A UK hospital dietetics page gives these practical points^[7]:

• Eat every 2 to 3 hours: about 3 small meals and 2 to 3 snacks.
• Aim for at least 1.2 g of protein per kg of body weight (about 96 g for an 80 kg adult), from sources such as tofu, chicken, turkey, eggs and dairy.
• If you eat normally without ill effects, keep doing so. If fruit, nuts, spicy or fatty foods bother you, reduce them.
• Chop, blend or well-cook fruits and vegetables, which can make fiber easier to tolerate.

If you have a stricture (a narrowed section of bowel), the AGA suggests careful chewing and cooking plant foods until soft rather than cutting them out, so you can still get fiber and variety^[1].

If you are asked to follow a low-fiber or low-residue plan, our guide to the low-fiber diet explains how those plans work and how to return to fiber.

Which foods should you avoid with Crohn's?

There is no verified universal list. The NIDDK says specific foods have not been shown to cause or worsen Crohn's symptoms^[2], and the hospital page we read states there is no clear link between Crohn's and specific food allergy or intolerance, though some people notice triggers^[7]. What the sources do support:

• Lactose, if you are intolerant. Many people with Crohn's digest lactose poorly. If you cut milk, replace the calcium; the page advises 1,000 mg a day for people with Crohn's^[7].
• Individual triggers. The page names fruits, nuts, and spicy or fatty foods as examples some people find worsen symptoms^[7].
• Prolonged elimination. Trial-and-error exclusion should be supervised and short, because it can cause deficiencies. One structured approach is the low-fat, fiber-limited exclusion diet (LOFFLEX) for reintroduction^[7].
• Ultra-processed foods (see below).

Do ultra-processed foods make Crohn's worse?

They may, but the data are observational. In the PURE cohort of 116,087 adults followed a median of 9.7 years, eating five or more servings of ultra-processed food daily was linked to a hazard ratio of 1.82 for developing IBD versus under one serving, with consistent results for Crohn's and ulcerative colitis^[16]. In 111 adults with Crohn's in remission, high intake was linked to relapse (HR 3.86, 95% CI 1.30 to 11.47) over a median of 12 months, and 21.6% relapsed^[17]. These studies show association, not cause.

The AGA nonetheless advises limiting ultra-processed foods^[1].

Does fiber help or hurt in Crohn's?

It depends on the disease phase and any narrowing. A 2023 meta-analysis of 11 studies (2,389 people) concluded fiber might improve remission rates, but only 2 were randomized trials and the authors rated the evidence as low quality^[18]. The umbrella review found higher fiber intake was inversely associated with Crohn's incidence, and low fruit, vegetable and fiber intake was linked to a higher incidence or progression of IBD overall^[15]. Meanwhile, a hospital dietitian page notes that cutting insoluble fiber helps some people with diarrhea, pain and gas^[7].

In practice: reduce tough, skin-on or seedy plant foods during flares or with a stricture, and rebuild variety in remission.

Which nutrients do people with Crohn's often miss?

Crohn's can reduce absorption through inflammation, medication or surgery^[2]. The AGA says everyone with IBD should be monitored for vitamin D and iron deficiency, and people with extensive ileal disease or ileal surgery for vitamin B12^[1]. It also recommends regular malnutrition screening, including for unintended weight loss^[1]. Ask for blood tests rather than guessing, and check supplements with your doctor first^[2].

What does the gut microbiome have to do with it?

CDED was designed to cut exposure to dietary components that may harm the gut microbiota, immune response and barrier^[10]. In the pediatric trial, remission on CDED plus PEN was associated with lasting reductions in inflammation markers and in fecal Proteobacteria^[3]. The NIDDK says some experts believe the microbiome plays a role in Crohn's, and that eating a variety of healthy foods can improve beneficial gut bacteria^[2]. Those are early signals, not a basis for self-directed changes.

Our Crohn's disease microbiome protocol and our profile of Faecalibacterium prausnitzii go deeper on the bacteria involved, and our page on inflammatory bowel disease covers the wider group.

When to see a doctor

See your gastroenterologist promptly, and seek urgent care for severe symptoms, if you have:

• severe or worsening belly pain or repeated vomiting, which can signal a blockage^[6];
• blood in your stool, fever or diarrhea that does not settle^[7];
• unintended weight loss or signs of malnutrition^[1];
• plans to start CDED, enteral nutrition or an elimination diet. Ask for a registered dietitian first^[1].

If a similar-sounding diet is aimed at another gut condition, our diverticulitis diet guide shows how those recommendations differ.

This article is for general educational purposes and is not medical advice. Diet can support but does not replace treatment for Crohn's disease, and trial results in small groups may not apply to you. Talk to a qualified healthcare professional or registered dietitian before changing your diet, starting supplements or stopping medication, particularly if you are pregnant, immunocompromised, taking prescription medication, or managing a diagnosed condition.