CHAPTER XX 



NUTRITIONAL REQUIREMENTS. FASTING. PARENTERAL 



NUTRITION 



NUTRITIONAL REQUIREMENTS 



THE streams of nutritive material which are poured into 

 the body have been followed from the very start, not with- 

 out interruption to their exit, but up to the point where 

 they disappear in intermediate metabolism, somewhat like 

 waterways whose courses are suddenly interrupted and lost 

 in the depths of a labyrinth of underground caves and pas- 

 sages. At this time it is desirable to deal more fully not so 

 much with the individual types of food as such, but rather in 

 a sense with their effects. The present lecture, therefore, 

 may properly be devoted to the problems of nutritional re- 

 quirement, of inanition, and of restricted diet. We enter 

 here directly into a field of study looked upon by the older 

 physiologists, so to say, as the science Ka r to X yv of me- 

 tabolism. 



Amount of Food. In calculating the normal nutritional 

 requirements of an individual, for a long time "Voit's 

 dietetic allowance" was used as a basis. According to this 

 118 grams of protein, 56 grams of fat and 500 grams of 

 carbohydrate were regarded as the proper requirement of a 

 healthy human being of about seventy kilograms weight. 

 Taking Rubner's standard figures, according to which one 

 gram of protein yields 4.1 calories, one gram of either starch, 

 glycogen or sugar 4.1 calories, but one gram of fat 9.3 

 calories, the total calory requirement foots up in round num- 

 bers three thousand calories. A long list of studies, among 

 which may be especially mentioned those of Rubner, Zuntz, 

 Tigerstedt, Atwater and Benedict, and Chittenden, 1 have 



1 Literature upon the Amount of Normal Food Requirement : A. Magnus- 

 Levy, v. Noorden's Handb. d. Pathol. d. Stoffw., 2d ed., 1, 319-330, 1906; 

 0. Cohnheim, Physiologic der Verdauung und Ernahrung, pp. 400-460, 1908. 



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