36 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



individuals having a low metabolism per kilogram of body-weight or 

 per square meter of body-surface. While we are convinced that the 

 so-called law of surface area is not so rigid in its application as its 

 warmest advocates would like to believe, the numerous deviations 

 from this law do not provide evidence as to any particular class or 

 group of individuals with a low metabolism, although the high metab- 

 oUsm of athletes has been experimentally demonstrated. 



PURPOSE AND PLAN OF PRESENT RESEARCH. 



Since one or two classes of individuals, even though abnormal, show 

 a lowered basal metabolism mainly as the result of a considerable degree 

 of emaciation, it is a legitimate question as to whether or not a dietetic 

 regime which leads to a moderate loss of flesh in normal subjects may 

 not result in a lowered basal metabolism. Undernutrition is caused 

 by a deficiency in food intake; this deficiency may be due either to a 

 deficiency in protein or in calories in the diet.^ 



Protein intake. — The problem of a reduced food intake has received 

 attention from physiologists for several generations, but interest has 

 been centered for the most part upon the possibility of lowering the 

 intake of protein. As the result of the heroic experiments of Professor 

 Chittenden and his school at New Haven, the idea has gained credence 

 (certainly with the American public and practically all physiologists) 

 that a large protein intake is neither necessary nor desirable; on the 

 other hand, that there should be an extensive reduction in protein is by 

 no means accepted by all. One may sum up the situation by stating 

 that the experiments of Professor Chittenden have unquestionably 

 had a strong influence upon physiological thought in favor of a material 

 reduction in the protein intake. It is safe to say that to most minds the 

 reduction in protein is desirable mainly from an economic standpoint 

 rather than from absolute physiological danger due to the ingestion of 

 so-called ''enormous " amounts; but it is undoubtedly true that a reduc- 

 tion in protein may certainly be made without danger. The most 

 important point, however, at the present time is not the question of 

 protein intake, but that of the total energy intake. 



Energy intake. — It is a conmion household observation that people 

 eat too much, the popular quantitative expression being that ''people 

 eat twice as much as they ought." Almost every household has its 

 dietetic peculiarities, one individual eating very heartily, while another 

 is said to eat "hardly enough to keep a canary alive." Yet careful 

 studies of groups of individuals living under the same conditions show 

 that ordinarily the total food consumption for like groups of individ- 

 uals does not vary widely, and it would thus appear that the intake of 



1 Although without bearing on this research (see page 260), the detrimental effects of a defi- 

 ciency in the so-called food accessory substances must not be overiooked in any basic 

 consideration of undernutrition. 



