Calorie Needs of Older People With Restrictive Eating Disorders Undergoing Refeeding

While historically viewed as illnesses of youth, restrictive eating disorders (EDs), including anorexia nervosa, restricting subtype (AN-R), and avoidant/restrictive food intake disorder (ARFID), affect women of all ages, yet there is limited understanding of effective interventions and best practices for refeeding of older patients. This study examined whether age affects kcal needs during refeeding and whether caloric needs differ between diagnoses.

In this retrospective cohort study, average kcal needs for a one-point increase in body mass index (BMI) were assessed for 417 female patients receiving inpatient medical stabilisation for AN-R or ARFID, comparing females < 20 years of age, 20-29, 30-39, and 40+ years using linear regression and chi-square tests of independence.

Average kcals needed for a one-point increase in BMI was 1870 kcal (SD = 1410). Average kcals needed per one-point increase in BMI were not statistically different amongst the age groups (p = 0.30). Patients with AN-R needed significantly fewer kcals than patients with ARFID for a similar amount of weight gain.

In this high-acuity inpatient sample, caloric needs for weight restoration were similar across age groups. Patients with ARFID required more calories than those with AN-R. Age-based prescription reductions may therefore be unwarranted, supporting individualised, diagnosis-informed refeeding.