Diet as Essential Therapy (DIET) for Inflammatory Bowel Disease

Recent data suggest that diet in inflammatory bowel disease (IBD) may lead to both symptom control and disease remission. Historically certain diets have been recommended for patients with Crohn's disease during exacerbations despite lack of data supporting efficacy. The investigators propose to evaluate two such diets by randomizing 32 subjects with mildly to moderately active Crohn's disease to one of two diets that differ in the amount and type of carbohydrates and fiber. Subjects will remain on the diet for 8 weeks and will be evaluated for changes from baseline in inflammatory biomarkers, symptomatic disease activity, and the microbiome.

Subjects will be randomized in a 1:1 ratio to receive one of two diets that are thought to be beneficial for Crohn's disease for a period of 8 weeks.

Initial evaluation will include a clinic visit with physical exam, medication review, supplemental documentation, and labs. Patients will be asked about their food allergies and intolerances against a master list of all ingredients used in both diets. Patients will then be provided with instructions on how to record their baseline dietary intake for two weeks prior to the intervention diet.

At day 0 patients will begin their study diet. All study meals will be provided to the subject and an approved snack list for the randomized diet will be provided in a sealed envelope with their first week of meals.

At the conclusion of intervention patients will be asked to resume their previous diet for 4 weeks and record their dietary intake. Stool and blood will be collected at baseline and at 4, 8, and 12 weeks. At the conclusion of the study patients will be told which diet they were on and will be provided with dietary consultation by a registered dietitian.

Subjects who withdraw from the study before the 4 week assessment will be asked to provide a final stool sample at the time of withdrawal. If more than 2 subjects drop out prior to week 4, subject replacement will occur.

Eligibility Criteria:
Inclusion Criteria:

* Consentable adults of age 18 or older.
* Diagnosis of Crohn's disease made by a primary gastroenterologist based upon history, physical exam, laboratory/radiological studies, and endoscopy with biopsy.
* Fecal Calprotectin ≥ 300
* Mild to moderate disease activity based upon a modified Harvey Bradshaw Index score of 5-16.
* On stable medication doses for ≥ 2 months.

Exclusion Criteria:

* Inability/unwillingness to adhere to dietary recommendations.
* Allergy or intolerance to any major component of the diets. Major component defined as an ingredient which, when left out of intervention diets, may affect study outcomes.
* Allium intolerance
* Exclusively vegetarian diet
* Active intra-abdominal or perianal abscess/fistula
* Symptomatic bowel stricture
* Other serious medical conditions such as neurological, liver, kidney, autoimmune, or systemic disease
* Use of corticosteroids within 1 month prior to baseline visit
* Tobacco, alcohol, or illicit drug abuse
* Pregnant subjects
* Celiac disease
* Patients already on one of the diets being studied
* C. difficile or other enteric infection (O\&P, stool enterics)
* Antibiotic use within 2 months prior to baseline visit