USDA cooking yields and retention factors are important because they serve as a major resource for U.S. and international food composition databases. Most public and private sector databases apply cooking yields to nutrient values as part of the nutrient calculation process where analytical data for cooked foods are unavailable. Composition data are needed for the nutrient value for both the uncooked and cooked forms of foods, but nutrient data for cooked foods are generally not available. Therefore, nutrient composition of a cooked food may be calculated from the uncooked food by applying cooking yield factors to these data to reflect changes in food weights resulting from moisture and fat losses during cooking.