192 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



minutes. If the tasks were correctly performed, a total score of 100 

 points could be made. 



In a later chapter the data will be given for the preceding 17 neuro- 

 muscular and psychological measurements. No tests were tried and 

 discontinued. 



STATE OF NUTRITION. 



With adults the demand for food is of two kinds. First, there is the 

 temporary demand which is determined in large part by idiosyncrasy, 

 by appetite, the season, the variety of the supply, and the environ- 

 ment. This is in large part psychological and has fully as much to do 

 with the quality of the food and manner of serving as with the amounts 

 actually eaten. Second, in comparison with this we have the perma- 

 nent demand as represented by the total amount and energy content of 

 the food eaten rather than by any transitory changes resulting from 

 whims of appetite or individual caprice. 



The body requires food to meet its needs for repair and maintenance 

 and to keep the weight at the normal level. When there is a persistent 

 loss in body-weight, this is an index that too little food is being taken. 

 When there is a persistent gain, too much food is eaten. Just what is 

 the best weight for the normal adult will be discussed subsequently, but 

 with any weight, deviations are produced by either too much or too 

 little food. 



Food is also required by the body to maintain its usual state or plane 

 of nutrition. When the body has been educated to living upon a high 

 nutritional level, there is a distinct demand for food to maintain this 

 level. When it has been educated by necessity or otherwise to a lower 

 level for a long time, the question arises : will the return of a plethora 

 of food supply affect the food habits or will there be a tendency to 

 maintain the low level? 



Finally, the dietetic habits reflect in large part the state of euphoria 

 or well-being of the individual. If he does not feel well, he usually eats 

 less. With free selection of food, man usually eats until he feels satis- 

 fied and is quite disinclined to eat less than will produce this feeling. 

 Frequently to secure this he eats a larger amount than he needs. 



Undernutrition, as commonly interpreted, implies not only loss of 

 weight, but frequently emaciation to such a degree that it is visible, 

 even to an alarming extent. Pathologists, on the other hand, state that 

 undernutrition may exist without ocular evidence of waste. This is not 

 so conflicting as may at first appear, for it is increasingly evident that 

 by undernutrition must be understood not merely the loss of a visible 

 proportion of fat to body-structure, but also a disturbance of the state 

 of well-being of the neuro-muscular organism, thus affecting the effi- 

 ciency. Any dietetic regime which produces this disturbance may, in 

 the absence of an obvious pathological lesion, for purposes of discussion 

 at least, be termed undernutrition. 



