Compositions and methods for the treatment and management of adult polyglucosan body disease (APBD) are disclosed herein. The APBD patients studied in the present invention experienced stabilization of disease progression and limited functional improvement with dietary triheptanoin (C7TG). The amount of C7TG administered to the patient daily for 6-8 months was 1-2 g/kg/24 hrs. The present invention demonstrates, for the first time, the arrest of clinical deterioration with limited functional recovery in APBD with triheptanoin diet therapy.