Anorexia nervosa (AN) is a severe mental disorder. Body shape disturbances are key in the development and maintenance of AN. Only few data are available on inpatients with life-threatening AN. Therefore, we aimed to investigate if body shape difficulties—with a focus on both body checking and avoidance—could improve during hospitalization in both subtypes of AN and to ascertain eventual associations between body shape concerns upon admission and clinical outcome.

Upon hospital admission and end of treatment (EOT), 139 inpatients with AN completed Body Shape Questionnaire (BSQ), Body Checking Questionnaire (BCQ), and Body Image Avoidance Questionnaire (BIAQ) in addition to measures of eating and general psychopathology.

Patients with severe AN reported improved BSQ and BIAQ scores at EOT while BCQ did not significantly change. Diagnostic subtypes differed only in baseline BSQ scores and had an impact on the improvement in BSQ at EOT. Baseline BCQ was associated with patients’ clinical improvement at EOT, even after controlling for age, duration of illness, Body Mass Index, depression, and anxiety scores.

Data on body shape concerns and their trajectory during hospitalization for severe AN are lacking; our findings provide support to the effectiveness of hospitalization in improving body shape concerns and body avoidance, but not body checking. Also, baseline body shape concerns (especially body checking) impacted on clinical improvement. Future research is needed to identify treatments that could further improve the therapeutic approach to severe patients of AN in the acute setting.

Traditional approaches for the classification of eating disorders (EDs) attribute symptoms to an underlying, latent disease entity. The network approach is an alternative model in which mental disorders are represented as networks of interacting, self-reinforcing symptoms. This project was the first to use network analysis to identify interconnected systems of ED symptoms.

Adult participants (n = 143; 77.6% women) with a Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) ED were recruited from the community to take part in a larger ongoing longitudinal study. The Structured Clinical Interview for DSM Disorders (SCID-I) was used to establish diagnoses. An undirected network of ED symptoms was created using items from the Eating Pathology Symptoms Inventory (EPSI) and the R package qgraph.

Body checking emerged as the strongest and most important single symptom in the entire network by having the shortest average distance to other symptoms in the network, and by being the most frequent symptom on the path between any two other symptoms. Feeling the need to exercise every day and two symptoms assessing dietary restraint/restricting emerged as ‘key players’, such that their removal from the network resulted in maximal fracturing of the network into smaller components.

Although cognitive–behavioral therapy for EDs focuses on reducing body checking to promote recovery, our data indicate that amplified efforts to address body checking may produce stronger (and more enduring) effects. Finally, results of the ‘key players analysis’ suggested that targeting interventions at these key nodes might prevent or slow the cascade of symptoms through the ‘network’ of ED psychopathology.