Role of the Nasal Environment in Obesity

Inclusion Criteria: N=50 adult male and female patients with obesity will be included in this study. Inclusion criteria: Inclusion criteria: * Age 18-55 years * Written informed consent * BMI \> 30 kg/m2 N=50 adult lean patients age- and sex-matched to the group of obese patients will be included in this study. Inclusion criteria: * Age 18-55 years * Written informed consent * BMI 18-25 kg/m2 N=50 adult male and female patients with obesity with scheduled bariatric will be included in this study Inclusion criteria: * Age 18-55 years * Written informed consent * BMI \> 35 kg/m2 Exclusion Criteria: * Smoking * Chronic or acute sinusitis * Surgical intervention of the nasal cavity or the paranasal sinus * Use of antibiotics within the last 31 days18 * Current illicit drug abuse including daily marijuana or CBD consumption (≤ 24 g of alcohol per day allowed) * Any kind of severe chronic disease (e.g. severe heart failure, active cancer disease) * Use of any kind of decongestant more than twice a week * Use of cortisone-containing nasal spray within the last 3 months * Acute allergic rhinitis * History of neurodegenerative diseases * History of severe head trauma * Severe renal impairment (e.g. estimated glomerular filtration rate \<30 ml/min/m2)