Basics in clinical nutrition: Substrates used in parenteral and enteral nutrition - Energy

-Energy needs should be determined in relation to expenditure, but also to the ability of a patient to metabolize substrates correctly.-Most hospitalized patients present a combination of stress and malnutrition. Their energy expenditure is often lower than values obtained from classical equations and textbook tables. The vast majority of patients, including those in ICU, have energy expenditures, which do not exceed 2000 kcal/d.-Aiming at achieving positive or zero nitrogen balance via hypercaloric support should be discouraged during the acute metabolic phase of sepsis or trauma.-Overfeeding during acute illness may be associated with major complications and side effects.-The target should consist of preserving function and limiting major depletion of lean body mass by starting nutritional support at an early stage, but with limited amounts of energy substrates. Hence, partial (under) feeding is acceptable during the hypermetabolic phase, while increased energy intakes may be useful in the recovery or anabolic phase of illness when tissue rebuilding is possible. © 2008 European Society for Clinical Nutrition and Metabolism.SCOPUS: sh.j