The kilojoule is a unit of energy used in food labeling throughout the European Union, Australia, and other countries. One calorie is equivalent to 4.184 kilojoules. It is abbreviated kJ. See: Calorie.
The human body metabolizes energy to function; this energy is quantified as kilojoules. Health agencies recommend, in general, approximately 8,700 kilojoules a day to meet daily energy requirements. Physical activity, body mass and composition, and other factors may alter these requirements.