Metabolism Experiment No. 70. 85 



Metabolism Experiment No. 70. 



Metabolism experiment No. 70, which differs from those previously reported 

 in this publication in that food was eaten, offers opportunity to study in 

 connection with the effect of inanition upon metabolism the effect of the 

 subsequent ingestion of food. 



In order to accumulate data in regard to the interrelations of fasting and 

 eating on metabolism, several such experiments were made, the subject remain- 

 ing inside the respiration chamber throughout both the fasting and the food 

 periods. Experiments Nos. 69 and 70 together form the first series of this 

 type. 



After 4 such series of experiments had been made, however, this method 

 of observation was discontinued for the following reasons. The results of 

 a large number of experiments had shown that the transition from the fasting 

 to a food period must not be too abrupt. This conforms with the experience 

 of all professional f asters, who practice a gradual transition in order to readjust 

 their bodies to the digestion of food. But since one of the important factors 

 in studying metabolism by means of the respiration chamber is to secure a 

 preliminary condition more or less uniform with that obtaining during the 

 experiment itself, it was obvious that, on the transition day at least, the meta- 

 bolic processes of the body have a transitional activity between that of complete 

 fasting and of full digestion of food, and hence the processes of metabolism 

 during the first day or two were not uniform. Moreover, it became apparent 

 that there was a tendency on the part of the subjects to shorten the duration 

 of the fasting period when they realized that after the fast there would still 

 remain a 2- or 3-day stay in the chamber. 



The interpretation of the results of metabolism experiments and the compu- 

 tations showing the material katabolized in the body, the proportions of 

 nutrients absorbed from the food ingested and the gains or losses to the body 

 may be made according to many methods. In the fasting experiments the 

 method of computation is relatively simple, as the only factor involved is the 

 amount of material actually katabolized. But on the contrary, when food 

 is ingested, and especially in that class of experiments in which the ingestion 

 of food immediately follows fasting, the conditions are not as satisfactory for 

 employing the method commonly used in metabolism experiments. It is 

 commonly assumed that when a metabolism experiment is made during which 

 the subject is subsisting on a constant diet, the contents of the alimentary tract 

 are in general constant, i. e., the absorption of food is continuous in that the 

 proportions of ingested protein, fat, and carbohydrates in the alimentary tract 

 do not indicate marked variations from day to day. In such cases, it may be 

 assumed that at the beginning of the experiment and at the end like conditions 



