Search results
Results from the WOW.Com Content Network
The calorie is a unit of energy that originated from the caloric theory of heat. [ 1 ] [ 2 ] The large calorie , food calorie , dietary calorie , kilocalorie , or kilogram calorie is defined as the amount of heat needed to raise the temperature of one liter of water by one degree Celsius (or one kelvin ).
For thermochemistry a calorie of 4.184 J is used, but other calories have also been defined, such as the International Steam Table calorie of 4.1868 J. In many regions, food energy is measured in large calories (a large calory is a kilocalory, equal to 1000 calories), sometimes written capitalized as Calories. In the European Union, food energy ...
Some organisms have instead anaerobic respiration, which extracts energy from food by reactions that do not require oxygen. The energy contents of a given mass of food is usually expressed in the metric (SI) unit of energy, the joule (J), and its multiple the kilojoule (kJ); or in the traditional unit of heat energy, the calorie (cal).
The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions .
The word energy derives from the Ancient Greek: ἐνέργεια, romanized: energeia, lit. 'activity, operation', [4] which possibly appears for the first time in the work of Aristotle in the 4th century BC. In contrast to the modern definition, energeia was a qualitative philosophical concept, broad enough to include ideas such as happiness ...
A nutritional Calorie is equivalent to a thousand chemical or thermodynamic calories (abbreviated "cal" with a lower case "c") or one kilocalorie (kcal). Because food energy is commonly measured in Calories, the energy density of food is commonly called "caloric density". [7]
A calorie deficit prompts your body to tap into stored energy reserves — primarily fat — to make up for the shortfall. This is what ultimately leads to weight loss.
According to the FAO, the average minimum daily energy requirement is approximately 8,400 kilojoules (2,000 kcal) per adult and 4,200 kilojoules (1,000 kcal) a child. [3] This data is presented in kilojoules, as most countries today use the SI unit kilojoules as their primary measurement for food energy intake, [ 4 ] with the exception of the ...