Nutritional rehabilitation with weight restoration is an important step in patients hospitalised for anorexia nervosa (AN). Naso-gastric feeding (NGF) should be considered when oral nutrition (OF) and oral nutritional supplementation (ONS) are insufficient. We evaluated the role of NGF on short- and long-term outcomes, considering weight gain, the length of hospitalisation (LOS) and the time to relapse. We report on the characteristics of patients under 18 years of age with AN admitted to the Department of Emergency and Acceptance of the Bambino Gesù Children’s Hospital, IRCCS, Rome, between March 2019 and August 2022. Three hundred and fifteen patients were enrolled. We compared patients treated with NGF (group A) and patients without NGF (group B). Group A was characterised by a significantly lower BMI on admission and discharge, more frequent use of inpatient psychotropic therapy (IPDT) and longer hospital stay. The time to relapse was significantly longer in group A compared to group B. An early NGF setting correlates with a longer time to relapse and may be associated with a shorter LOS. A high caloric intake with a balanced nutritional formula provided by NGF allows an earlier recovery. The main advantages of this approach could be the rapid discharge of patients and a more effective psychological and social recovery.