Errors in the calculation of the nutritive value of food intake. 1. Comparison of calculated and determined amounts of calories, protein and fat.

/CALCULATION of the nutritive value of foods using tables of food com^ position, is a commonly used procedure in hospitals and in private medical practice for the control of special diets and in nutritional surveys for the determination of the adequacy of the food supply. For example, in the reports of surveys recently published in this Journal (1) it was noted that records of the weights of all food consumed by the observed persons were kept. Using a set of tables of food composition issued by the Canadian Council on Nutrition, calculations were made of the nutritive value of the consumed food in terms of calories, protein, fat, etc. These values were then compared with a dietary standard and the degree of adequacy of the food intake was assessed. Obviously, it is of importance to determine possible sources of error, if significance is to be attached to the final evaluation.