kCal

A kilocalorie (kcal) is a unit of energy commonly used to express the energy content of foods and beverages. In nutrition, the term calorie is often used to refer to a kilocalorie, though the official SI unit is the joule. One kilocalorie equals 1,000 small calories.

The energy content of foods is typically determined using standardized energy values. The Atwater general factors assign about 9 kcal per gram for fat, 4 kcal per gram for carbohydrate, 4 kcal per gram for protein, and 7 kcal per gram for alcohol. Dietary energy labels may present calories as "Calories" (with a capital C), which correspond to kilocalories.

For most adults, daily energy requirements vary with age, sex, weight, height, and activity level. Consuming more energy than the body expends leads to weight gain, while a deficit leads to weight loss. Energy balance is a central concept in nutrition and weight management.

In physics terms, 1 kcal equals 4.184 kilojoules (kJ).

Limitations: the actual usable energy from foods can vary due to digestion and metabolism. The Atwater factors are estimates, and foods with fiber or non-digestible components may yield less metabolizable energy than their total kilocalorie content suggests.