MONTREAL, July 28, 2025 – Early-onset restrictive eating disorders, such as anorexia nervosa and avoidant/restrictive food intake disorder (ARFID: see note below), may be linked to structural changes in the developing brains of affected children, according to a new study led by Clara Moreau, a researcher at the Centre de recherche Azrieli du CHU Sainte-Justine. Using magnetic resonance imaging (MRI) scans from children aged 7 to 13 years old diagnosed with anorexia nervosa or with severe ARFID, the research team identified significant brain alterations unique to each disorder. While some of these changes are associated with weight loss during a critical period of brain development, the study also highlights disorder-specific effects. Encouragingly, the findings suggest that many of these changes may be at least partially reversible.

This is the first study to document the impact of ARFID on brain morphometry, and one of the few to examine early-onset anorexia nervosa – a less common form of the disorder that emerges before puberty.

Beyond Weight Loss: Distinct Neurological Signatures

By comparing the brains of children with anorexia nervosa to those with ARFID, the researchers demonstrated that the neurological impact of these disorders is not only due to low body weight. Although all participants with an eating disorder had a low (<16) body mass index (BMI), the brain alterations differed markedly between the two groups.

“In children with anorexia, we observed a pronounced and widespread thinning of the cerebral cortex,” explains lead investigator Clara Moreau, who is also Assistant Professor at Université de Montréal’s Faculty of Medicine. “This phenomenon has recently been documented in adolescents and adults with anorexia, suggesting a significant impact on the brain regardless of the age at diagnosis.” Approximately half of this cortical thinning appears to be linked to rapid weight loss.

In contrast, children with ARFID did not show cortical thinning. Instead, they exhibited reduced intracranial volume and gray matter. Despite similar BMI levels, these changes do not appear to be driven by underweight status. “Because ARFID often begins earlier and progresses more gradually than anorexia, it’s possible that the brain and metabolism manage to adapt to the dietary restrictions, which might explain the preserved cortical thickness in these children,” Moreau suggests.

Supporting Brain Recovery to Prevent Relapse

The study also found that brain structure can recover with weight restoration. When comparing children at different stages of their medical treatment, the researchers observed that structural differences tended to diminish as BMI increased. “This is very promising, as it suggests that full neurological recovery is possible when treatment begins early and relapses are limited,” says Moreau.

Looking ahead, Moreau and her team plan to pursue longitudinal research incorporating functional brain imaging to better understand how brain function evolves during recovery. They aim to establish a cohort of children followed at the CHU Sainte-Justine Eating Disorders Clinic and leverage the advanced imaging technologies available at the hospital’s Centre IMAGINE.

“We know that about one-third of young patients hospitalized for anorexia will relapse within a year of discharge,” Moreau notes. “Could this be linked to incomplete brain recovery? And if so, could we predict relapse risk to better support the most vulnerable children?”