4 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



Furthermore, there is lacking that careful scientific balance which is 

 necessary to demonstrate an actual lowering of the metabolism to 

 compensate, in part at least, for the lower food-intake. It appeared 

 to us that if the German civilian population had found it possible 

 under war conditions to subsist on these low rations and had ap- 

 parently adjusted themselves to an entirely new and heretofore prac- 

 tically unrecognized nutritional level, the scientific foundation for 

 this change was certainly worthy of exact study. Furthermore, such 

 research seemed especially timely, as the attention of a large number 

 of American people was, in 1917, directed towards the conservation 

 of food; it was accordingly important to analyze critically the factors 

 that play the chief role in such conservation. Strenuous efforts had 

 been made to reduce the consumption of certain food materials, such 

 as sugar, wheat products, and animal products, by advocating the 

 substitution of other materials, but one factor had previously been 

 for the most part neglected, i. e., the possibility of a reduction in the 

 amount of food consumed. The general problem of reducing the 

 total food consumption quantitatively could not, however, be seriously 

 considered by the laity. In view of the emergency confronting this 

 nation in 1917, it was natural that the importance of food conserva- 

 tion should likewise occupy the minds of practically all physiologists. 

 The question therefore arose with the Nutrition Laboratory: Is it 

 possible by any dietetic regime to lower the total amount of food 

 consumed and not at the same time disproportionately lower effi- 

 ciency for either intellectual or muscular activity? In other words, 

 is it possible to make a dietetic alteration of material moment which 

 will still enable individuals to carry on their general activities, both in- 

 tellectually and physically, as members of society, without appreciable 

 detriment? 



It has not been the custom of the Nutrition Laboratory to direct its 

 researches primarily for economic and sociological purposes; yet in 

 view of its long-continued study of people with a low intake of food 

 and conceivably low metabolism, and the not remote possibility that 

 America might be obliged to undergo privations similar to those in 

 Germany, although probably in less degree, it seemed eminently fitting 

 for the Laboratory to study a question so important from the stand- 

 points of patriotism, economy, and physiology, as the effect upon the 

 metabolism of a reduction in diet. The extensive research which is 

 reported in this publication is, in the last analysis, a furthering of the 

 initial problem studied by the Nutrition Laboratory, i. e., a search for 

 conditions resulting in subnormal metabolism. It was planned in 

 detail in the spring of 1917 and carried out during the winter of 1917-18 

 with a selected group of normal individuals whose body-weight was 

 lowered as a result of quantitative reductions in their diet. 



