There are no reports of controlled trials of management practices in anorexia nervosa, and a paucity of follow‐up data. We investigated the nutritional requirements of four adolescent females with the condition, and describe a management approach based on nutritional principles. The aim was to reverse the initial state of catabolism by enteral nutrition prior to any negotiation regarding oral energy consumption.The median age of presentation was 14.15 years (range 14–16.1 years). All girls had abnormal perceptions relating to food and phenotype. The median weight loss in the preceding 6 months was 27% (range 21–33%). At presentation the median energy intake was 2710 kJ per day (range 2083–4166 kJ) and represented a median of 26% of that expected. The mean initial energy requirements to reverse the state of severe malnutrition were 14 634 kJ per day. The median time to regain 50% of lost weight was 44 days.Energy requirements in this disease have been underestimated by both patients and caregivers. Supplementing oral intake with energy‐dense defined formulae delivered by nasogastric tube is a safe and rapid method of achieving nutritional rehabilitation in the early stages of self