Mechanism of FODMAP Restriction on FGID Patients

Inclusion Criteria: * Aged 18 and above * Able to provide informed consent * Those with pre-existing irritable bowel syndrome (IBS) or functional dyspepsia (FD) or both screened by gastroenterologists * Meet the ROME III- Asian criteria for FGID * Able to communicate in Malay or English language Exclusion Criteria: * Pregnant or lactating women * History declared by the participant of pre-existing gastrointestinal disorder, including but not limited to Inflammatory Bowel Disease, Coeliac Disease, Pancreatitis, Gallstone disease (biliary colic, cholecystitis), Diverticulitis * Cancer of any kind * Patients with reported history of previous resection of any part of the GI tract other than appendix or gall bladder, intestinal stoma * Habitual use of opiate analgesics likely to alter bowel function e.g. morphine * Use of antibiotics in the preceding two weeks and/or in the past one month * Consumption of probiotics, prebiotics or fibre supplements in the past one month * Enteral feeding or texture modified diet patients * Those with cognitive impairment or severe mental disorder (Alzheimer's, schizophrenia, bipolar disorder. etc) * Shift workers (e.g. Nurse, doctors)