Calorie conversion factors. An experimental reassessment of the factors used in the calculation of the energy value of human diets
- 1 June 1970
- journal article
- Published by Cambridge University Press (CUP) in British Journal of Nutrition
- Vol. 24 (2), 517-535
- https://doi.org/10.1079/bjn19700050
Abstract
1. The intake and excretion of total nitrogen, fat and the various forms of carbohydrate, and the heats of combustion of the diet, urine and faeces were measured in groups of young men, young women, elderly men and elderly women.2. Each group was studied while the subjects were eating two diets in turn, which differed in their contents of unavailable carbohydrate; the young women were also studied on a third diet which was rich in unavailable carbohydrate.3. Increasing the intake of unavailable carbohydrate resulted in a greater faecal loss of energy, and in most instances of nitrogen and fat.4. There was no significant effect of sex or age on the apparent digestibility of protein, fat or available carbohydrate.5. The results are used to evaluate the use of calorie conversion factors for calculating the metabolizable energy content of mixed diets.6. These show that for practical purposes the classical Atwater factors can be used to calculate the metabolizable energy of a diet with reasonable accuracy, provided that when available carbohydrate (as monosaccharides) values are used in the calculation a factor of 3.75 kcal/g (15.7 kJ/g) is used.7. The studies demonstrate that the accuracy of any method for calculating the metabolizable energy of a diet is largely determined by the accuracy with which the method is capable of predicting the gross energy of the diet.Keywords
This publication has 15 references indexed in Scilit:
- Determination of carbohydrates in foods. I.—Available carbohydrateJournal of the Science of Food and Agriculture, 1969
- Determination of carbohydrates in foods II.—Unavailable carbohydratesJournal of the Science of Food and Agriculture, 1969
- Effect of Reduced Protein Intake on Nitrogen Loss from the Human IntegumentThe American Journal of Clinical Nutrition, 1967
- Nitrogen Excretion in Sweat and Its Relation to Nitrogen Balance RequirementsJournal of Nutrition, 1963
- Some Difficulties in Estimating the Energy Value of Human DietsProceedings of the Nutrition Society, 1955
- Methods of Assessing the Energy Values of Foods for Ruminant AnimalsProceedings of the Nutrition Society, 1955
- The digestibility of English and Canadian wheats with special reference to the digestibility of wheat protein by manEpidemiology and Infection, 1947
- The total nitrogen content of egg albumin and other proteinsBiochemical Journal, 1943
- The micro-determination of urea in blood and other fluidsBiochemical Journal, 1937
- LAWS GOVERNING THE CHEMICAL COMPOSITION OF URINEAmerican Journal of Physiology-Legacy Content, 1905