Clinical Research Directory

Inclusion Criteria: Group 1: * Age 18-75 years * BMI 18.5-25 kg/m² * Normal glucose tolerance (Fasting glucose \< 5.6 mmol/L) Group 2: * Age and sex-matched with group 1 * BMI≥30 kg/m² * Impaired glucose tolerance (Fasting glucose 5.6 - 6.9 mmol/L) Exclusion Criteria: * Diabetes mellitus type 1 or type 2, or fasting plasma glucose \> 7.0 mmol/L * Treatment with GLP-1 receptor agonists or other GLP-1-based therapies within the past three months * Use of medication affecting appetite, body weight, or glucose metabolism within the past three months * Current eating disorder (anorexia nervosa, bulimia nervosa) * Known serious chronic disease, including but not limited to: * Heart disease * Anemia (hemoglobin \<7.0 mmol/L for women, \<8.0 mmol/L for men) * Renal impairment (eGFR \<60 mL/min/1.73m²) * Hepatic impairment (ALT or AST \>3 times upper limit of normal) * Known monogenic obesity * Substance abuse (current or within the past year) * Previous bariatric surgery * Contraindications to study procedures, including: * Esophageal or nasal obstruction (e.g. tumors, strictures) * Coagulopathy * History of skull base trauma * Esophageal varices * Hiatal hernia * Claustrophobia * Inability to comply with MRI requirements (e.g. remaining still) * Presence of non-removable magnetic objects incompatible with MRI * Any other condition or circumstance that, in the opinion of the study physician, may compromise safe participation in the study. Exclusion criteria for women: * Pregnancy, breastfeeding, or wish to become pregnant during the study period * Women of childbearing potential not using adequate contraception * Women using hormonal contraception (oral contraceptives, progestin- containing implants or hormonal intrauterine device.)