The central objective of this proposal is to test a novel diet capable of meeting the elevated protein requirements in ulcerative colitis (UC), while simultaneously decreasing microbial hydrogen sulfide (H2S) production in the colon with fiber.

Inclusion Criteria:

• Ability and willingness to provide informed consent

• Age at least 18 years old

• Diagnosis of UC based on clinical and endoscopic criteria

• UC duration of at least 3 months

• Ulcerative Colitis Endoscopic Index of Severity (UCEIS) score ≤4 within 90 days of randomization

• On a stable dose or no existing UC therapies (apart from steroids) for defined periods (as outlined below).

  1. ≥4 weeks if no medication, 5-ASA
  2. ≥8 wk for immunomodulatory therapy
  3. ≥12 wk for biologics

• Ability to comply with study requirements in the opinion of the primary investigator

Exclusion Criteria:

• Moderate or severe UC as defined by UCEIS ≥5
• History of stomach surgery or bowel resection
• Antibiotic use within 3 months
• Anticipated antibiotic exposure during the study period (e.g. perioperative antibiotics)
• Pregnancy or breastfeeding
• History of anaphylactic food allergies
• Intolerance of high dietary fiber content
• Ongoing alcohol or drug abuse
• Habitual vegan diet pattern
• Insufficient freezer space to accommodate meal delivery