Functional dyspepsia is common, affecting 7.2% of the global population, and associated with substantial health impairment. Almost 80% of patients with functional dyspepsia report meal-related symptoms and are classified as having the postprandial distress syndrome (PDS) variant. However, studies evaluating dietary modifications in PDS are sparse. The investigators will perform a single-centre randomised trial evaluating traditional dietary advice (TDA) in PDS. 50 patients with PDS will be randomly assigned to a leaflet explaining reassurance-alone +/- TDA. The reassurance-alone group will be informed of the absence of organic disease and provided a diagnostic explanation of functional dyspepsia. The TDA group will receive the same information but also be recommended to eat smaller, regular meals and reduce the intake of caffeine/alcohol/fizzy drinks, fatty/processed/spicy foods, and fibre. Questionnaires are to be completed during the 4-week trial, including self-reported adequate relief of dyspeptic symptoms, and the validated Leuven Postprandial Distress Scale (LPDS), Gastrointestinal Symptom Rating Scale, and Napean Dyspepsia Quality of Life Index. The primary endpoint(s) to define clinical response will be evaluated over weeks 3-4 as, i) ≥50% adequate relief of dyspeptic symptoms, and ii) \>0.5-point reduction in the PDS subscale of the LPDS (calculated as the mean scores for early satiety, postprandial fullness, and upper abdominal bloating).