Calorie

A calorie refers to a non SI unit of energy. There are two common but different meanings: one is used in food and nutrition, the other was formerly widely used in chemistry, and a food calorie represents 1000 chemistry calories. The food calorie is sometimes capitalized as Calorie to distinguish it from the chemistry calorie; however, this capitalization is rarely observed in practice.

Nutritionists measure the energy content of food in "calories" (usually capitalized and abbreviated as Cal or sometimes C), where each food calorie represents 4,186 joules. This is equivalent to 1000 of the calories used in chemistry, and thus the food Calorie would more accurately be called a kilocalorie. However, in chemistry calories have been deprecated as a scientific unit of measure in favour of joules, and therefore in common modern usage the word "calorie" will usually refer to a food calorie.

This situation provides two ways of talking about the amount of calories in food which look quite different but that express the exact same amount of energy. One may say that dietary fat has 9 kcal per gram, while proteins and carbohydrates have 4 kcal per gram, or, one may say that fat has 9 Calories per gram while carbohydrates and proteins have 4 Calories per gram.

The amount of food energy in a particular food is measured by completely burning the food in a bomb calorimeter, a method known as direct calorimetry
(http://www.merck.com/mmhe/sec12/ch152/ch152e.html).

Dieticians recommend counting calories to avoid obesity. The government of the United Kingdom recommends consumption of 2000 Calories (2000 kcal) by women each day and 2500 Calories (2500 kcal) by men each day.

Related in Calorie;

Calories Needed To Maintain

Calories Burned During Exercise

For Further Information go to Nutritional Supplements Directory