How Are Calories Calculated in Food?
Other People Are Reading
-
What Is a Calorie?
-
A scientific calorie is a measurement that reflects the amount of energy produced. When measuring calories in food, a scientist is calculating the expected output of energy, or how much energy the food will produce for the person consuming it.
A dietary calorie is a unit called a kilocalorie, which is equal to 1,000 scientific calories. A dietary calorie, or kilocalorie, is the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius.
Atwater System
-
Scientists use the Atwater System to determine the amount of calories in a specific food by breaking it down into energy-containing nutrients. Each of these nutrients is weighed according to how many grams of each are present in the item, then the numbers are added together to get the total number of calories in a food.
Energy-containing units generally have a measurable amount of non-soluble fiber. Because the body does not use non-soluble fiber to produce energy, the amount of fiber present in the units is subtracted from the dietary-calorie calculation.
-
Nutrients' Value
-
Different nutrients have different values in the Atwater System, and knowing the values is key to calculating calories in food. Protein, carbohydrates, alcohol and fat are the nutrients measured when calculating the dietary calories (or kilocalories) in an item.
According to the Atwater System, protein is worth 4 kilocalories per gram; carbohydrates are worth 4 kilocalories per gram; alcohol is worth 7 kilocalories per gram; and fat is worth 9 kilocalories per gram. For example, a food with 8 grams of protein, 5 grams of carbohydrates, 0 grams of alcohol, 2 grams of fat and 0 grams of non-soluble fiber would be worth 70 calories.
-
