700 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



reduction of propagation. These warnings must certainly be heeded. 

 Precisely the same factors that reduced normal sex expression in these 

 men may, however, be of extreme practical importance in pathological 

 phases of sexual perversions. 



The introspection shows clearly that not a little of the mental unrest 

 was caused by the fact that others were eating liberally and freely 

 and the social element was removed or repressed. 



Certain possible procedures that in times of stress might be justi- 

 fiably recommended, at least as war measures, have been considered 

 recently in reporting some of the data from this research.^ This is 

 not the place to enter into any discussion of the practical application 

 of these diets to immediate economic national problems. It is, how- 

 ever, perfectly justifiable to make conclusions as to the practicability 

 of a reduced diet in food stringencies. Entirely aside from war or 

 any factors pertaining thereto, food stringencies will inevitably occur 

 throughout the world as a result of accident, floods, climatic disturb- 

 ances, etc. To instill into the world at large a belief that a pronounced 

 lowering of rations is not necessarily accompanied by a complete dis- 

 integration of the organism and collapse of mental and physical 

 powers may, after all, be of real service. A reduced ration may be a 

 minimum, but this is far from saying that it is an optimum. Experi- 

 mental evidence has accumulated in sufficient amounts to justify a 

 serious consideration of a material reduction in the intake of protein, 

 which is one of the most expensive factors in human food. It is not 

 clear that a low-protein diet is harmful. Indeed, much of the evidence 

 now points to the fact that a low-protein diet is without harmful 

 effects upon the organism. 



One of our unsolved problems in this research is the relationship 

 between body protein and metabolic level. If the lowered general 

 metabolism is due to the absence of protein in the body — and our 

 evidence points strongly towards this — we may then argue that while 

 in times of stress the minimum and lower level is justifiable and reason- 

 ably safe, in times of plenty the optimum is a higher protein level. 

 The reduction of body-weight without loss of body-nitrogen is a 

 scientific situation that should be thoroughly investigated. Our data 

 throw no light on this subject. Obviously the diet could be so adjusted 

 as to keep up the supply of body-nitrogen for the most part and still 

 draw from body-fat. Until experiments of this type are made with 

 accuracy and in sufficient numbers to settle this question without 

 doubt, the amount of the optimum protein intake must be held in 

 abeyance. For a tentative war measure the question of low protein 

 need not seriously be contested. The recent marvelous developments 

 as a result of the study of the so-called ''food accessory substances" 



^Benedict, Proc. Am. Phil. Soc, 1918, 57, p. 479. 



