Clinical Research Directory

Inclusion Criteria: * Patients with ulcerative colitis and planned proctocolectomy with ileoanal j-pouch anastomosis surgery or patients who are to undergo subtotal colectomy. * Age over 18 years. * Written informed consent to take part in the study. * Speaking ability in Greek or English. * Able to get tested fasted; Exclusion Criteria: * Age under 18 years. * Existence of pregnancy. * Inability to breathe inside the indirect calorimetry mask for the time required for the measurement. * Use of medications that may affect body metabolism will be evaluated individually (e.g. cortico-steroids etc.)