The staff responsible for preparing this food will be members of the digestive diseases unit at the NIHR Nottingham Biomedical Research Centre and will not be involved in the study otherwise. The investigators responsible for MRI and symptom analysis will be kept blind to the intervention as data will be coded by date of study day, rather than by product received. Additionally MRI data will be assigned a 'scanning number' through the Sir Peter Mansfield Imaging Centre. This will pseudo-anonymise MRI data within the study so that associations between participants and scans will not be immediately obvious.