The "Calorie" has become a common household term. Dietitians recommend, in cases of obesity, to reduce body weight by increasing exercise (energy expenditure) and reducing energy intake (consumption of food). But that is only part of the story. This chart helps put this into perspective.
Many governments require food manufacturers to label the energy content of their products, to help consumers control their energy intake. In Europe, manufacturers of prepackaged food must label the nutritional energy of their products in both kilocalories ("kcal") and kilojoules ("kJ"). In the United States, the equivalent mandatory labels display only "Calories" (when used with capitalized C, meaning kilocalories); an additional kilojoules figure is optional. The energy content of food is usually given on labels for 100 g and for a typical serving size.
Food is oxidized after consumption. In oxidation by consumption, heat is released. Within the body, this heat is released as energy of metabolism. The rate of energy production is called the metabolic rate.