Figure 2.

Cellular energy used in adaptive thermogenesis. (A) The total energy expenditure of the mouse can be divided into four components: basal metabolic rate, physical activity (green), the thermal effect of food (red) and cold-induced thermogenesis (blue). At room temperature (20–22 °C) more than one third of the total energy expenditure is cold-induced thermogenesis, which is required to maintain body temperature. (B) The energy used for cold-induced thermogenesis is mainly produced by skeletal muscle shivering and BAT thermogenesis.