Calories

A calorie is a unit used to measure energy. In nutrition, the word "calorie" usually refers to a kilocalorie (kcal), which is the amount of energy needed to raise the temperature of one kilogram of water by one degree Celsius. The body obtains calories from carbohydrates, proteins, fats and, in adults, alcohol.

Carbohydrates and proteins provide about 4 kcal per gram, fats about 9 kcal per gram and alcohol about 7 kcal per gram. This energy allows the body to perform essential functions such as breathing, maintaining body temperature, circulating blood, repairing tissues, thinking and moving. Even during sleep, the body continues to use calories to support vital processes.

The number of calories a person needs each day varies according to age, sex, body size, physical activity, health and other individual factors. Eating more calories than the body uses over a long period can lead to excess energy being stored, mainly as body fat, while consuming too few calories may cause weight loss if the energy deficit continues.

However, the nutritional quality of food is just as important as its calorie content. Foods with the same number of calories can provide very different amounts of vitamins, minerals, fiber and protein. For this reason, a healthy diet focuses not only on the amount of energy consumed but also on choosing a wide variety of nutritious foods that meet the body's needs.