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.