438 



NOURISHMENT FOR A HEALTHY ADULT. 



The minimum amount of proteid requisite for preserving the nutrition must 

 be so large that the nitrogen it contains will be equal to the nitrogen excreted by 

 the individual in question in a fasting condition. 



Small animals consume for each unit of body-weight decidedly more than 

 large ones. This depends not so much on the fact, as was formerly believed, 

 that the metabolism is more active in small animals, as on the fact that small 

 animals, in proportion to their body-weight, possess a larger body-surface, and 

 are, therefore, more exposed relatively to external influences, and especially to 

 the cooling effect of the surrounding air. If the amount of the substances de- 

 composed is compared, not to the body- weight but to the body-surface, for 

 example to one square meter, almost the same values will be obtained for small 

 is for large animals of the same species. On the other hand, the values for animals 

 of different species are different. 



The absolute amount of food that an adult requires in twenty-four 

 hours is most conveniently expressed in the form of units of energy 

 that it is capable of supplying, that is, in calories. An adult, with a 

 moderate amount of fat, requires daily, for each kilogram of body- 

 weight : 



At complete rest from 32,000 to 38,000 calories. 



At light work 35,ooo " 45,000 



At hard work 50,000 " 70,000 



Therefore, a man weighing 70 kilograms at light work would require 

 in the neighborhood of 70 X 40,000, or 2,800,000 calories. Any diet 

 containing 2,800,000 calories is sufficient; but the diet must always 

 contain proteid and in no event less than 80 grams daily. As i 

 gram of proteid yields 4100 calories, i gram of carbohydrate 4100 

 calories and i gram of fat 9300 calories, the following dietetic combina- 

 tions may be considered as sufficient: 



Grams. Calories. 



80 of proteid = 328,000 



300 of carbohydrate .... = 1,230,000 



113 of fat = 1,237,000 



2,795,000 



80 of proteid = 328,000 



265 of fat = 2,465,000 



100 of proteid 



280 of carbohydrate 

 133 of fat 



2,793,000 



= 410,000 

 = 1,148,000 

 = 1,237,000 



2,795,000 



Grams. Calories. 



80 of proteid = 328,000 



200 of carbohydrate .... = 820,000 

 177 of fat = 1,646,000 



2,794,000 



328,000 

 1,640,000 

 828,000 



80 of proteid 



400 of carbohydrate . . . 

 89 of fat 



For a short time also: 



60 of proteid 



320 of carbohydrate . 

 133 of fat 



2,796,000 



246,000 

 1,212,000 

 1,237,000 



2,795,000 



In most of the ordinary articles of food nitrogenous and non-nitrog- 

 enous substances occur together, but, as the statements on page 435 

 show, in widely different proportions. Man requires a diet in which 

 the proportion between nitrogenous and non-nitrogenous substances is 

 between 1:3^ and i : 4^. If a person takes food in which this propor- 

 tion does not hold, he must consume an excessive amount of it, in order 

 to obtain a sufficient quantity of that substance in which the article 

 of diet is relatively deficient. This, it is clear, must necessarily cause 

 waste of the preponderating substance. Moleschott has, in this con- 

 nection, grouped the principal articles of diet together. In order to 



