The ability to do work. The SI unit of energy is the joule, and nutritionally relevant amounts of energy are kilojoules (kj, 1000 J) and megajoules (MJ, 1000 000 J).
Measured in kilocalories or kilojoules. One calorie equals 4184 joules.
The force or strength to carry out activities.
The fuel value, usually measured as calories or joule, available to the body by chemical transformation (burning) of carbohydrates, fats and proteins, and used for mechanical activity, replacement of heat lost and purposes of growth.
Energy is often defined as the capacity to do work. Several forms of energy are extremely important in human physiology and biochemistry. These forms include chemical energy, such as ATP and macronutrients from food; mechanical energy, such as that which occurs with movement during a muscle contraction; heat, which is produced as a byproduct of metabolism and maintains thermoregulation; and electrical impulses.
The calories provided by food used for the body’s growth, tissue repair, and physical activity. In nutrition, calories represent the amount of energy contained in foods or the amount of energy expended by a person. To maintain a constant weight, the amount of energy or calories supplied by the diet should not exceed the amount of energy a person expends. Growth and recovery from injury, illness, or surgery increase an individual’s energy requirements. Carbohydrates and fats are the body’s main sources of energy. Excess energy is stored in the body as fat.
In physics, the capacity to do work, that is, to effect change. Energy is manifested in motion (kinetic energy) or position or chemical bonding (potential energy).
The capability to bring about modification; it is quantified by the magnitude of effort executed amidst a designated alteration.
Energy is the ability to perform work or bring about physical changes. Nutritionists use this term to describe the fuel content of a food.
There exist numerous forms of energy, encompassing light, sound, heat, chemical, electrical, and kinetic energy, and many of them serve essential functions in the body. For example, the retina, located at the back of the eye, transforms light energy into electrical nerve impulses, enabling vision. Moreover, the body’s muscles utilize chemical energy derived from food to generate kinetic energy, facilitating movement and producing heat.
Energy is quantified using two units: calories and joules. However, due to their small size, the field of dietetics (nutritional science) relies on more practical units, such as the kilocalorie (kcal) and kilojoule (kJ). One kilocalorie is equal to 1,000 calories, and one kilojoule is equivalent to 1,000 joules. When it comes to macronutrients, carbohydrates and proteins supply 4 kilocalories per gram (g), while fats provide 9 kilocalories per gram (g).
Typically, the energy released during the breakdown of food is stored as chemical energy in ATP (adenosine triphosphate) molecules. This stored energy becomes accessible to fuel various energy-consuming processes in the body, like muscle contractions or the repair and maintenance of bodily structures.