Rationale for Determining Energy Requirement in Hospitalized Patients: A Narrative Review

Malnutrition is common among hospitalized patients and negatively affects clinical outcomes. Therefore, appropriate nutritional support is essential to enhance recovery and survival. Accurate determination of energy requirements is a key component of effective nutritional therapy. Energy expenditure (EE), which determines energy requirements, can be measured directly by indirect calorimetry or estimated using predictive equations. However, because indirect calorimetry is not always feasible in clinical practice, predictive methods based on basal metabolic rate (BMR) are widely used. This narrative review summarizes the physiological basis of energy requirements and the components of total energy expenditure (TEE)-including BMR, physical activity, thermic effect of food, and growth, amount of energy to overcome disease-and compares recommendations from major international guidelines for adult and pediatric patients. It also highlights the importance of continuous monitoring and adjustment according to clinical response.