To determine whether a lacto-ovo vegetarian diet is effective in improving gastrointestinal symptoms, quality-of-life, intestinal inflammation and gut microbiota composition in mild-to-moderate IBD compared to a standard omnivorous diet.

This study will review whether a lacto-ovo vegetarian diet is an optimal dietary therapy to achieve a clinical response in mild to moderate UC and CD as an adjunctive treatment to current medical therapies. The proposed studyT will be used to evaluate the efficacy of a lacto-ovo vegetarian diet together with its effect on the microbiota to create an enhanced understanding of the role diet plays in the management midl to moderate IBD. Using a socially acceptable diet it is anticipated that food-related quality-of-life measures will improve for participants. Dietary modification could be a more economical, safer and more effective means of reducing symptoms and flare-ups compared to pharmacological therapy.

Inclusion Criteria I. Is able to provide informed consent. II. Is over the age of 18 years. III. Has a diagnosis of ulcerative colitis or Crohn's disease for over a 3-month duration that was confirmed by a specialist gastroenterologist IV. Pro-6 score of 2 to 4, partial mayo 3-6 (mild to moderate UC) or Harvey Bradshaw Index (HBI) 5 to 15 (Crohn's disease)

V. Medications:

1. Oral 5-Aminosalicylates: If taking an oral 5-Aminosalicylates the patient has used them continuously for 4 weeks and has been on a stable dose for 2 weeks prior to the screening visit.
2. Oral Corticosteroids: If taking oral corticosteroids the patient has used them continuously for 4 weeks and has been on a stable dose for 2 weeks prior to the screening visit at a dose of ≤30mg.
3. Oral Azathioprine/6MP, Methotrexate or tacrolimus: If taking one of these medications the patient has used them for a minimum of 12 weeks and has been on a stable dose for 4 weeks prior to screening.
4. Biologic therapy with infliximab, adalimumab or vedolizumab: If taking one of these medications the patient has used them for a minimum of 12 weeks
5. Rectal Preparations; 5-Aminosalicylates, corticosteroids or tacrolimus: If taking one of these medications the patient has used them continuously for 4 weeks and has been on a stable dose for 2 weeks prior to the screening visit.

VI. Willing to participate in the study and comply with the proceedings by signing a written informed consent.

VII. Free of any clinically significant disease, other than ulcerative colitis/Crohn's disease, that would interfere with the study's evaluations.

VIII. Subjects can read and understand English and is able to adhere to the study methodology and visit schedules.

Exclusion Criteria

I. Has been on antibiotics within the last four weeks. II. Has a known food allergy to nuts, soy, eggs or dairy. III. Is pregnant or breast feeding. IV. Following a vegetarian, vegan or low FODMAP diet. V. Has known dementia and the inability to understand the trial requirements. VI. Ulcerative colitis: Patients with less than 15cm of disease (proctitis) VII. Crohn's disease: Patients with severe Disease (HBI > 15) or remission (HBI<5) VIII. Patients with active extraintestinal disease, current B2 (Fixed non inflammatory stricture1 or small bowel obstruction) or B3 disease (Boneh et al, 2017)

All data will be de-identified

Due to the nature of this type of dietary intervention it is not possible to blind the participant nor treating gastroenterolgist