kilocalorias

Kilocalorie, commonly abbreviated kcal, is a unit of energy used in nutrition to quantify the energy provided by foods and beverages. In this context, the Calorie (with a capital C) is equivalent to one kilocalorie. One kilocalorie equals 1,000 small calories and is approximately 4,184 joules.

Food energy is typically reported in kilocalories or kilojoules (kJ) on nutrition labels. In general usage, the term "calorie" on food packages refers to kilocalories, not the thermodynamic unit, though the distinction is sometimes overlooked.

Measuring energy involves two approaches. The gross energy of a food can be determined with a bomb calorimeter, while the energy available to the body (metabolizable energy) is estimated using conversion factors such as the Atwater factors: protein 4 kcal/g, carbohydrate 4 kcal/g, fat 9 kcal/g, and alcohol 7 kcal/g.

Uses and interpretation. Kilocalories are used to plan dietary energy intake and to assess energy balance. Actual needs vary by age, sex, weight, and activity level, but typical daily targets for adults commonly fall around 1,800 to 2,500 kcal, with adjustments for goals and health status.

Limitations. The body's energy extraction depends on digestion and metabolism; not all consumed calories are absorbed or utilized, and foods differ in nutrient quality and satiety. Therefore, kcal values provide a guide rather than a precise predictor of weight change. In Spanish, kilocalorías are often referred to as kilocalorías (kcal) or simply calorías on nutrition labels, with the term Caloría used for the kilocalorie in everyday language.