Calorie – A measurement of the amount of energy that is either in various foods, or that is burned off as a result Maintaining one’s calorie balance is very important for preventing and controlling overweight and obesity. More information, including the formula for calorie balance can be found in our Section on Overweight and Obesity. In addition, our Food and Fitness Channel provides many delicious low calorie recipes, and its Fitness Branch provides many helpful tips for burning off calories. Calories are also the fuel used by the body for its various functions, such as breathing, circulating the blood, and physical activity. When a person is sick, their body may need extra calories to fight fever or other problems.