A unit of energy equivalent to one million joules, abbreviated MJ. In nutrition and food science, the megajoule expresses large energy quantities: daily human energy requirements are typically 8 to 12 megajoules, and the energy content of bulk foods or diets is conveniently stated in these units. Food energy labelling in countries using the metric system often shows kilojoules per 100 grams, with megajoules used for daily totals and industrial calculations. Engineers use megajoules to quantify the energy in fuels, heating processes, and refrigeration loads. The unit links dietary energy to the SI system, with one megajoule equal to about 239 kilocalories.