Demographic data and anthropometric measurements will be obtained for baseline assessment. Patients are required to complete FGI Screening Questionnaire, Functional dyspepsia symptom questionnaire, gastroesophageal reflux disease (GERD) symptom questionnaire and irritable bowel syndrome (IBS) symptom questionnaire to have a thorough assessment of their GI symptoms. (1) Satiety test and ghrelin profile, and (2)gastric emptying test will be arranged as two individual visits.