Following from this, the investigator would like assess the feasibility and reproducibility of using MRI imaging to assess gastrointestinal transit. The investigator would like to recruit 21 healthy volunteers to measure orocaecal transit time (OCTT) and whole gut transit(WGT)using the conventional method of Lactose-C13 Ureide breath test for OCTT and the Metcalf method using standard radio-opaque pellet method for WGT and compare them will MRI imaging. Once this has been analysed and the best method for each OCTT and WGT have been decided, these methods would be applied in Study 2.