Stomach Processing and Emptying Evaluation With Diet and Ultrasound

Inclusion Criteria: * Age between 18 and 40 years * Ability and willingness to provide written informed consent * Agreement to comply with study procedures, including pre-study dietary restrictions * No history of gastrointestinal disease * No recent abdominal surgery Exclusion Criteria: * Lack of informed consent * Allergy or intolerance to any of the foods used in the study meals * Medical conditions known to delay gastric emptying, including: * Obesity (BMI \> 30 kg/m²) * Diabetes mellitus * Gastroesophageal reflux disease (GERD) * Hiatal hernia * Bowel obstruction * Tube feeding * Active gastrointestinal disease * History of gastrointestinal surgery * Current pregnancy or breastfeeding * Use of medications affecting gastric motility (e.g., opioids, anticholinergics, GLP-1 receptor agonists) * Neuromuscular disorders impairing ability to remain in supine position for 6 hours or to walk for 30 minutes