1920] FOODS HUMAN NUTRITION. 61 



resources and food consumption of the United States covering tlie period from 

 1911 to 1918, inclusive. 



The survey consisted essentially of a study of the amount of protein, fat, and 

 carbohydrate annually produced in the United States in forms usable for human 

 food, the proportions of these basic nutrients imported and exported annually, 

 the amounts annually consumed as human food, their distribution among the 

 several classes of food commodities, and the proportion of the total nutrient 

 material consumed by domestic animals. For the purpose of the statistical 

 analyses all nutritive materials produced and consumed were classified as (1) 

 primary foods, including all plant materials used as human food or fractions 

 of such materials, and all animals or animal products in which the animal gets 

 its nourishment from some source other than the primary feeds and fodders 

 as defined below; (2) primary feeds or fodders, including all plant materials 

 or 1^-actions of such materials used for the nourishment of domestic animals ; 

 and (3) secondary foods, including all e<lible products of animals used for 

 human food, the animals being nourished with primary feeds and fodders. 

 These classes were further subdivided into those used directly as harvested, 

 without other sophistication than cooking, and those in a derivative or manu- 

 factured form. 



The Year Books and the Monthly Grop Reports of the U. S. Department of 

 Agriculture were used as the main sources for the production figures of primary 

 products, and trade papers, census returns, etc., for the secondary products. 

 Export and import figures were taken in main from official reports compiled 

 by the U. S. Department of Commerce. In the compilation of nutrient values 

 the factors of Atwater and Bryant were chiefly used. In reducing consump- 

 tion data to a per capita basis the man-factor values adopted were from 0-5 

 years of age, 0.5; 6-13, 0.77; 14-18, males 1.00; 14-18, females 0.83; 19 on, 

 male, 1.00 ; and 19 on, female, 0.83. The data throughout are expressed in both 

 tabular and diagrammatic form. 



In the final chapter, the consumption of human food in the United States, 

 the calculations of food production, importation, and exportation in the pre- 

 ceding chapters have been utilized to determine the annual consumption in 

 the United States of 20 or more staple commodities used as human food, and 

 to discuss several problems centering about human food consumption, includ- 

 ing (1) the relative degree to which primary as distinguished from secondary 

 human foods contribute to the total nutritional intake of the population of the 

 United States, (2) the relative proportion of the total nutritional intake fur- 

 nished by the different food commodity classes, and (3) the per capita per 

 diem consumption of food. 



In general, the consumption figures show great uniformity from year to 

 year. In the seven-year period considered, the greatest relative advance in con- 

 sumption was in respect to fat while protein showed a slight falling off. Carbo- 

 hydrate and calories of energy increased somewhat but to a less degree than 

 fat. Of the average protein consumption during the whole period, 47 per 

 cent came from primary sources and 53 from secondary sources, of the fat 18 

 and 82, carbohydrate 95 and 5, and calories 61 and 39 per cent, respectively, 

 from primary and secondary sources. Concerning the relative proportion of 

 the total food intake furnished by the different commodities, the grains were 

 first in the contribution of protein, carbohydrate, and calories ; meats were 

 first in fat and second in protein and calories; and dairy products were second 

 in fat and third in protein and calories. These three groups made up nearly 

 83 per cent of the total protein intake. The relative nutritional importance 

 of the several food commodities as indicated by their energy content measured 

 in calories was for the six years of 1911 to 1917 as follows : Wheat contributed 



