Does it take more calories to warm a body in sub-zero temperatures than to cool it in hot weather?
There is not much difference. Extremes of cold and heat each lead our bodies to burn more calories than at moderate temperatures. At low temperatures, our bodies produce additional heat through the generation of heat when food is digested. About five to 15 percent of the calories our bodies burn are responsible for the heat our bodies produce. However, how many calories are burned at either temperature extreme can be significantly influenced by an individual’s weight. Thin people expend more calories than overweight people. Cooling the body also requires more energy — to produce sweat and open capillaries, part of the process to vent heat from the body.