The neuropeptides, or their precursors, that will be studied in serum/plasma are peptides involved in regulation of satiety and digestion, e.g. cholecystokinin (CCK), gastrin, ghrelin, glucagon-like peptide-1 (GLP-1), and glucagon-like peptide-2 (GLP-2), leptin, motilin, neurotensin, oxytocin, and peptide YY (PYY). To evaluate permeability defects in the intestinal mucosa, levels of zonulin and bacterial endotoxins, i.e. lipopolysaccharides, will be measured in plasma. Low-graded inflammation is reflected by high-sensitive C-reactive protein (CRP), plasminogen activator inhibitor type 1 (PAI-1), and factors involved in AGE will be analyzed. In addition, different cytokines, tracers, and routine analyses will be performed. Cooperation with laboratories in Denmark and Great Britain will be established.