What Is a Food Calorie?

Your body burns food calories for energy.

Calories are a measure of energy. A food calorie indicates the energy content of food.

Other Names

A food calorie is also called a Calorie (written with a capital C), a kilocalorie, or a large calorie.

Properties

One calorie (written with a small c) is the amount of energy needed to raise the temperature of one gram of water one degree Celsius. A kilocalorie is 1000 calories. A food calorie is equal to a kilocalorie.

Measuring Calories

Physicists measure the energy content of food by burning it using a bomb calorimeter, which is a strong metal container surrounded by a water bath. The food is dried and ground into a powder and placed in the bomb calorimeter. The physicist then pumps pure oxygen at high pressure into the metal container to ignite the food, and measures the resulting energy release in calories.

Calories in Your Body

In a less explosive way than a bomb calorimeter, your body burns calories to create energy.

Calories in Food

According to Exploring Food Magazine, carbohydrates and proteins have about 4.2 food calories per gram and fats about 9.3 food calories per gram.

References

• What is Energy?
• Exploring Food Magazine; Counting Calories; Paul Doherty; Vol. 14 #4 1990