Inclusion Criteria:  BMI between 22 - 35 kg/m2  Exclusion Criteria:  intake of medication (cardiovascular diseases, lipid and glucose metabolism) chronic manifest psychical and psychiatric diseases participation in another study pregnancy or breastfeeding in the MRI/MRS sub-study, any MRI contraindication (claustrophobia, pacemakers, MR-incompatible prosthetic valves, metallic implants, foreign metallic body) active uncontrolled gastrointestinal disorders including ulcerative colitis, Crohn's disease, indeterminate colitis, severe irritable bowel syndrome, persistent infectious gastroenteritis, persistent or chronic diarrhea of unknown etiology, recurrent Clostridium difficile infection major surgery of the GI tract, in the past five years. Any major bowel resection at any time intake of antibiotics in the last 2 months