Background. Dyspeptic patients tolerate smaller meal loads than healthy subjects, but it is not known whether and to what extent symptoms relate to abnormal homeostatic or hedonic components of perception. Methods. Parallel studies in patients with symptoms induced by meals (fulfilling Rome IV criteria of postprandial dyspepsia) and sex- and age-matched healthy subjects. Participants will be instructed to eat a standard dinner the day before, to consume a standard breakfast at home after overnight fast, and to report to the laboratory, where the test meal will be administered 4 h after breakfast. Studies will be conducted in a quiet, isolated room with participants sitting on a chair. Participants will ingest a probe meal up to the level of maximal satiation. The probe meal will be served stepwise (112 Kcal every 5 min). Perception of homeostatic (hunger/satiation, fullness) and hedonic (digestive well-being, mood) sensations will be measured at 5 min intervals 10 min before, during and 20 min after ingestion at 10 min intervals.

Inclusion Criteria for Patients with Functional Dyspepsia:

• Rome IV Criteria for Functional Dyspepsia

Inclusion Criteria for Healthy Subjects

• absence of digestive symptoms

Exclusion Criteria for all participants:

• history of anosmia and ageusia
• alcohol abuse
• psychological disorders
• eating disorders

Inclusion Criteria for Healthy Subjects:

• non-obese

Exclusion Criteria:

• history of gastrointestinal symptoms
• prior obesity
• use of medications
• history of anosmia and ageusia
• current dieting
• alcohol abuse
• psychological disorders
• eating disorders