204 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



state of nutrition upon the various physiological and psycho-physi- 

 ological processes of a group of men. 



To tabulate the results of this research and prepare the material for 

 publication would have been an impossibility without the intense 

 cooperation of Miss Annie N. Darling, to whom the editorial revision of 

 the entire manuscript has fallen; of Mr. William H. Leslie, who, as 

 chief of the computing division of this Laboratory, has untiringly 

 labored to secure both rapid and accurate tabulation of the results; 

 and of Miss Elsie A. Wilson, who has unremittingly labored on much 

 of the abstracting, as well as the computing and tabulating. Our 

 obligation and gratitude to these cooperators is extreme. Mr. Leslie 

 was ably assisted by the Misses Frances E. Kallen, Anna M. Burns, 

 Marion L. Baker, Mary D. Finn, Mildred J. L. Manning, and Helen C. 

 Waldron. The drawings used in this report were for the most part the 

 result of the skilful attention of Messrs. Edward L. Fox and Alden K. 

 Dawson. 



DISCUSSION OF RESULTS. 



BODY-WEIGHT. 



According to our general plan of research, observations were to be 

 made upon these men, first, during a period of insufficient food, and 

 second, during a period of maintenance diet at a lower nutritional level. 

 The most obvious result of a reduction in the amount of food taken 

 is the loss in body-weight caused by the fact that body-reserves are 

 drawn upon to supplement the inadequate diet. Outside the physi- 

 ological laboratory, therefore, no method is so satisfactory for deter- 

 mining differences in nutritional level with special reference to drafts 

 upon or storage of body-material as long-continued observations on the 

 body-weight. Carried over a period of several days, if not weeks, 

 these are truly indicative of the state of the body-reserves. A careful 

 study of the body-weights of our squads, both prior to and subsequent 

 to diet reduction, is therefore of importance. 



To shorten the preliminary period of insufficient food in which the 

 subjects were brought to the lower nutritional level, it seemed desirable 

 to reduce the body-weight of the men as quickly as possible. The 

 reduction of body-weight has been the subject of a great deal of inves- 

 tigation, and many practical methods have been suggested and exten- 

 sively applied. These fall for the most part into a few well-defined 

 classes. First, the body-weight may be rather rapidly reduced by 

 complete fasting. During the 31-day fast made in this Laboratory the 

 body-weight fell about 1 pound for each day of complete fast, although 

 the loss was much more pronounced in the earlier part of the fast than in 

 the latter part. A second method is to reduce materially the food in 

 the diet. By giving less food than is actually required, the deficiency is 

 made up by drafts upon the body-material. Third, the reduction in 



