|The 4-4-9 Method|
|For USDA SR nutrient data for “formulated foods” (items with multiple ingredients), CyberSoft uses the “4-4-9 method” of calculating the “% of total calories from” and the “calories from” values for Protein, Carbohydrates, and Fat. In NutriBase, “PCF Ratio” refers to the percentage ratio of calories from Protein, Carbohydrates, and Fat. (NutriBase also offers a User Preference option to display the CPF Ratio, if preferred.)
The 4-4-9 method is an official AOAC method of calculating calories. Most laboratory analyses still report calories using this method. This popular method of estimating calories assumes that one gram of protein contains 4 calories, that one gram of carbohydrate contains 4 calories, and that one gram of fat contains 9 calories. In beverages or foods containing alcohol, it is assumed that each gram of alcohol provides 7 calories. By knowing the total calories in the food and the total calories from the calorie sources contained in the food, it is a fairly straight-forward calculation to determine the “Calories from” and the “% Calories from” values.
For USDA data, which uses the Atwater Conversion Factors for Protein, Carbohydrates, and Fats for most food items (except for formulated foods), CyberSoft performed calculations based on the factors provided by the USDA. The Atwater Factors used by the USDA are known to be more accurate than the AOAC-approved 4-4-9 method. The Atwater Factors are conversion factors that take into consideration that different types of foods provide different amounts of food energy per unit of any given calorie source. (See that Atwater Conversion Factors in this document to see the amount of variance you can expect to see in common foods.)
For USDA “formulated foods,” which include multiple ingredients, CyberSoft used the AOAC-approved 4-4-9 method of calculating calorie ratios. Doing so produced some calorie ratio totals of less than or greater than 100%. (CyberSoft’s policy regarding USDA data is to keep it “as-is.” For this reason, data from the original USDA source files have been retained unchanged.)
For food items listed in the Vitamins and Medical Nutritionals section of NutriBase (multiple vitamins, supplements, enteral and parenteral products), CyberSoft calculated calorie ratios by using the manufacturer's information regarding calorie percentages. (These values total 100%.)
This topic updated 06/24/2015