65 - Energy Requirements of Men and Women

Abstract

This chapter describes the current methods for assessing usual energy needs of an individual, and summarizes national recommendations on energy intake using extracts from the Dietary Reference Intakes (DRI) publication on energy and macronutrients. Energy requirement of an individual is defined in the Dietary Reference Intakes (DRI) publication of the Food and Nutrition Board as “the dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health.” Thus, energy requirements are equal to total energy expenditure (TEE) in weight-maintaining individuals. TEE is the sum of energy expended for different metabolic processes and activity, with three main components being typically defined: basal metabolic rate (BMR), energy expenditure for physical activity and arousal (EEPA), and thermic effect of feeding (TEF). The alternative approach to estimating energy requirements of summarizing measurements of TEE determined using the doubly labeled water method for groups of individuals of normal body weight. Equations developed from statistical modeling of measurements of TEE in healthy individuals now exist for predicting the energy requirements of groups and individuals from age, weight, height, and estimated level of physical activity. Other factors such as genetic inheritance, racial origin, and climate also exert some influence on energy requirements, for weight-maintenance of energy needs.