Validity of an AI-Assisted Dietary Recording Application for Family-Based Nutritional Management in Young Patients with Anorexia Nervosa

<b>Background</b>: Evidence regarding the validity of digital dietary recordings in the family-based nutritional management of anorexia nervosa (AN) remains limited. This study evaluated the validity of an AI-assisted dietary recording application (app) used by the parents of young patients with AN, with total energy intake as the primary outcome and major nutrient intake as the secondary outcome. <b>Methods</b>: During hospital leave prior to discharge, one day of dietary intake was recorded by parents using the app based on meal photographs. The energy and nutrient intakes estimated by the app were compared with a registered dietitian using visual estimation of the photographs. Differences were examined using the Wilcoxon signed-rank test, associations were assessed using Spearman's correlation coefficients, and agreement was evaluated using Bland-Altman analysis. Sensitivity analyses excluding extreme outliers were performed. <b>Results</b>: Thirty female inpatients with AN (mean age: 14.8 ± 2.9 years) and their mothers participated. The median total energy intake did not differ significantly between the app and reference method (2462 vs. 2439 kcal/day). Moderate to high correlations were observed for total energy (<i>ρ</i> = 0.62) and major nutrient intakes. The app tended to overestimate these intakes; however, Bland-Altman analyses indicated no systematic bias. Exclusion of two outliers strengthened correlations for total energy intake (<i>ρ</i> = 0.74) and narrowed the limits of agreement. <b>Conclusions</b>: The app demonstrated an acceptable agreement for estimating energy and major nutrient intake in the therapeutic context of AN. Careful attention to dish type and portion size may further support its clinical use.