The purpose of this study is: 1. To explore to what extent insulin sensitivity, energy metabolism and ectopic lipid storage can be improved by bariatric surgery 2. To explore to what extent hepatic and muscular disorders of energy metabolism occur in patients with obesity (degree 2-3) 3. To explore whether the steato liver occurring in patients with obesity (degree 2-3) is associated with the degree of liver inflammation
Inclusion Criteria: * Aged ≥ 20 years- ≤ 70 years * BMI 20- 25 kg/m 2 normal- weight group * BMI 35- 39,9 kg/m 2 (Obesity grade 2) * BMI \>40 kg/m 2 (Obesity grade 3) Exclusion Criteria: * Acute illness 2 weeks before start of examination * Autoimmune or Immune disorder diseases (Leukozyten \< 5000/µl * Renal insufficiency (Kreatin \> 1,5 mg/dl) * Heart disease, condition after heart attack * Anemia (Hb \<12g/l, controlled before every day of examination) or blood donations 4weeks before examination. * Participation in another trial within the last 2 weeks * Pharmacological- immunotherapy (Cortisol, Antihistaminika, ASS) * Thyroid disorders * Glitazone Therapy * Pregnancy, Lactation, Menstruation * Smoking cigarettes, Alcohol- and drug abuse * Psychiatric disorders * Risk for/ or diagnosed HIV/ AIDS or Hepatitis B/C * Liver disease, which are not caused by non- alcoholic steato- hepatitis * Working on night shifts or irregular rhythm of night- day * Impaired wound healing or clotting disorders * Allergic reaction to local anesthetics * Malignant cancer