3 Thus, DEE is 10% of TEE when one eats according to what one needs. DEE represents about 10% of the total amount of energy ingested for an average diet with 10–15 energy% from protein, 30–35 energy% from fat and the remaining energy from carbohydrate. Here, the focus is on body size, body composition and energy expenditure in subjects where adult height is reached, that is, age of 18 years and older.Īt adult age, the largest component of TEE for a moderately active subject is for body maintenance as measured under resting conditions. 2 The increase is reflected in an increase of the physical activity index (PAI=TEE/REE) from 1.4 to 1.75. 1 Activity energy expenditure as a fraction of TEE increases from 20% at age 1 to ~35% at age 18. Initially, energy requirement is mainly determined by growth and energy expenditure for body maintenance. Here, control of energy expenditure is reviewed by comparing TEE and the three components in relation to differences for the subject characteristics body size and body composition, followed by reviewing effects of changes in food intake and changes in physical activity on energy expenditure.įrom birth, children grow in weight and height, reaching adult values around the age of 18 years. Total energy expenditure (TEE) can be split in three components: maintenance or resting energy expenditure (REE) energy expenditure for the processing of ingested food or diet-induced energy expenditure (DEE) and activity-induced energy expenditure (AEE). Thus, this review is restricted to determinants including subject characteristics, food intake and physical activity. We stay in the thermal neutral zone by controlling the temperature of our homes and dress according to climatic conditions when going out.
We generally choose our environment to feel comfortable. In normal daily life, environmental factors like ambient temperature are negligible. Behavioral determinants of energy expenditure include food intake and physical activity. The main environmental determinant of energy expenditure is ambient temperature, where energy expenditure increases in a cold environment through shivering and in a hot environment through panting. A larger body, especially a larger fat-free mass, requires more maintenance and thus induces a higher basal metabolic rate or resting energy expenditure. Trained subjects have a higher performance at the same expenditure through a higher exercise economy.Įnergy expenditure in humans is determined by body size and body composition, environment and behavior. In untrained subjects, exercise induces a larger increase in total energy expenditure than can be attributed to the energy cost of a training program. An exercise-induced increase in activity expenditure is a function of the training status. In addition, energy restriction induces an adaptive reduction of energy expenditure through a lowering of tissue metabolism and a reduction of body movement. Food intake induces changes in energy expenditure as a function of changes in body size and body composition. Smaller and leaner subjects generally move more as activity energy expenditure in larger subjects is not higher in proportion to the cost of moving with a higher body weight. Activity-induced energy expenditure is the most variable component of total energy expenditure. Higher weight results in higher energy requirement through a higher resting requirement because of a higher maintenance cost of a larger body. Body size and body composition are the determinants of resting energy expenditure. Energy expenditure is determined by body size and body composition and by food intake and physical activity.
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