Explanation

Calories (Kcal) are measures of energy. Each gram of carbohydrates, protein and fats provides your body with a different amount of energy, and the higher the calories, the more energy you are taking in.

To stay healthy, the number of calories you eat must equal the number of calories your body uses. You need roughly between 500 and 2500 calories per day, but you should speak to a dietician to find out exactly how many you need.

Most packaged foods have their energy value written on the side in Kcal, and you can look at standard lists for foods that don't have any packaging.