Inclusion Criteria:  Patient scheduled for elective open pancreatoduodenectomy. Patient ≥18 years old. Patient at nutritional risk, i.e., with Nutrition Risk Screening (NRS) ≥3. Signed informed consent.  Exclusion Criteria:  Patient not able to give informed consent as documented by signature of consent form (e.g., vulnerable patients). Enteral feeding already initiated preoperatively. Language barrier. Inability to follow the procedures of the study, e.g., due to language problems, psychological disorders (i.e., eating disorders and bipolar disorders), or dementia.