Inclusion Criteria:  Eligible participants are all adults (≥16 years old) with active CD (defined as Crohn's Disease Activity Index ≥ 150) who are due to initiate standard adalimumab (TNFα antagonist) induction treatment (160 mg day 0, 80 mg at 2 weeks and then 40 mg every 2 weeks).  Exclusion Criteria:  Inability to provide written consent to participate in the study Pregnant and/or breastfeeding individuals Presence of stoma Presence of short bowel syndrome Previous treatment with an anti-TNFα inhibitor Use of any other biologic therapy or oral small molecule therapy within the last 12 weeks Patients currently receiving oral or intravenous steroids at a dosage >20mg/day prednisolone or >9mg budesonide Introduction of or change in dose of immunomodulator (azathioprine, mercaptopurine, methotrexate) within the past 8 weeks Use of oral antibiotics within the past 4 weeks CD with a major fistulising or symptomatic fibrotic stricturing phenotype Patients tested positive for blood-borne viruses such as HIV and Hepatitis Patients with untreated tuberculosis (latent or active) Current enrolment in other studies of an investigational product or dietary intervention Food allergies, which do not permit participation in the study (e.g., cow's milk allergy)