In addition, assessment of body composition via Dual Energy X-ray Absorptiometry (DEXA )scans and of energy expenditure via indirect calorimetry, respectively, will allow us to correlate GDF-15, Nfl and GFAP and cytokine levels with lean and fat mass measures as well as with energy expenditure, respectively, of AN patients and the matched controls. Overall, this will allow us to comprehensively evaluate GDF-15 and cytokines as possible novel targets for the treatment of AN and to set the basis for a follow up study using available neutralizing antibodies or inhibitors against GDF-15 and the respective cytokines for the treatment of patients with AN, respectively. This will also allow for a more tailored, individualized treatment approach of AN in the future. Our findings will hopefully challenge the viewpoint that AN is a condition which can be controlled by the individual but demonstrate that AN is a biological disease that should be treated by targeting the right biological players in addition to psychiatric treatment.