Individualized Study of Refeeding to Optimize iNpatient Gains

Atypical Anorexia Nervosa (AAN) is a new diagnosis describing patients with malnutrition and significant weight loss yet "normal" weight. These patients responded poorly to HCR, the superior refeeding treatment in the parent trial, which was designed for low-weight patients with typical AN. The proposed trial will examine the safety and efficacy of a new treatment for AAN with the potential to improve treatment outcomes for this diverse and growing patient population. The major finding motivating the proposed trial is that participants with AAN gained weight 40 percent slower and required 3.0 additional days in hospital to restore medical stability on HCR, as compared to AN. The research team has developed Individualized Caloric Refeeding (ICR), which doses calories to weight consistent with other pediatric treatments (e.g. medication). The primary purpose of the proposed trial is to compare the efficacy and safety of ICR to the new standard of care (HCR) in hospitalized patients with AAN. The investigators hypothesize that ICR will restore medical stability faster than HCR with no increase in electrolyte abnormalities. After hospitalization, the major barrier to care in AAN is lack of consensus on clinical remission and whether these formerly overweight patients should gain weight to recover. The research team will examine metabolic, hormonal and psychological markers during long-term follow-up, toward the goal of developing a definition of clinical remission in AAN. Design Summary: Randomized controlled trial in N=74 participants age 12-24 with AAN, consented upon hospital admission, randomly assigned to ICR or HCR, followed daily in hospital and at 3, 6, 9 and 12 mo.