The three energy expenditure components are basal metabolic rate, thermogenesis and thermic effect. Energy expenditure refers to burned calories versus calories consumed. Changes in weight are determined by the imbalance between the consumed and burned calories.
Basal metabolic rate is the energy burned when an organism is inactive. It is the energy expended when an individual is lying and resting after sleep. Thermogenesis concerns calories burned during vigorous activities and other activities through the day. The thermic effect of foods involves calories expended during food digestion. The body uses considerable amount of energy when processing some crude foods, such as meats and whole grains.