A method for measuring energy malnutrition in a liver disease test subject, a method for determining whether a liver disease test subject is in an energy malnutrition state, a method for determining the necessity of nutrition therapy for a liver disease test subject having energy malnutrition, a composition usable in these methods, and the like are provided. The method for measuring energy malnutrition in a liver disease test subject includes the steps of collecting expired air containing labeled carbon dioxide that is generated in the body of a liver disease test subject by being converted from a composition containing, as an active ingredient, glucose labeled with at least one isotope C； and determining the ratio of labeled CO2 amount to unlabeled CO2 amount, or the ratio of labeled CO2 amount to total CO2 amount in expired air.
