The SI unit of energy equal to 1,000 joules, abbreviated kJ. Food energy labelling in many countries, including Australia and the European Union, expresses energy content in kilojoules, with 1 kilocalorie equal to 4.184 kilojoules. Nutrition panels may show both units to help consumers familiar with calories. The kilojoule is also used in exercise physiology to quantify energy expenditure and in food engineering to describe heat transfer during processing. Because the numbers are roughly four times larger than kilocalorie values, shoppers switching between labelling systems should note the conversion. Standardised energy units allow consistent comparison of foods across brands and countries.