Investigation of the Evolution of Gastric Emptying by Gastric Ultra Sonography in Patients Treated With GLP-1 Receptor Agonists on a 7 Days Pausing Period.

Evaluation of cross sectional area of the antrum by gastric ultrasonography in healthy patients and in patient treated by GLP-1 receptor agonists after a fasting period (6 hours for solid and 2 hours for clear liquids). For the GLP-1 receptor agonists group the gastric ultrasonochography will be repeated each 2 days during 7 days. In the non GLP-1 receptors agonists group the evaluation will be executed one time.