UNDERNIITRITION 



TABLE 4 

 CALCULATED HEAT PRODUCTION OF FASTING MAN. (Levanzin) 



(Data for table from Benedict.) 



adjust itself to its intake in calories. If a man has been taking in his 

 food 3,500 Calories a day and his intake is changed to 2,400 Calories, the 

 heat production will be found to change from about 3,100 Calories (the 

 excess 400 being in non-available nutriment) to about 2,100 Calories. The 

 heat production is proportional to the intake within certain limits. The 

 extra heat on a high caloric diet does not come wholly from extra voluntary 

 muscular work, although some of it does for a man on a low diet will 

 usually conserve his energy and be moderate in his activity. Much of the 

 extra heat comes froni extra tissue activity. The above represents essen- 

 tially the theory of "luxus consumption" (Grafe and Graham (&), 1911). 

 With a fall in the caloric intake, there is usually a loss in weight, for 

 the heat production falls slower than the food intake. A man can adjust 

 his caloric production to equal his caloric intake down to a certain point, 

 but not beyond. With each lowering of the caloric intake there is usually 

 a loss of weight which, however, does not continue after the heat pro- 

 duction has adjusted itself to the intake. The question arises "How far 

 can the caloric intake be lowered and the heat production still adjust itself 

 to the new level ?" That would represent the critical point, which might 

 be said to be the dividing point between nutrition and undernutrition. 

 But on the other hand, it does not represent a level of optimum nutritional 

 efficiency, because with this low caloric level one usually finis dissatis- 

 faction, irritability and physical inactivity. Just what this level is varies, 

 of course, with the weight, age, etc. For the average adult weighing sixty 

 kg., it is about 1,600 Calories a day, while with babies it is about 60 Cal- 

 ories per kg. of body weight. These figures above are for individuals lead- 

 ing a sedentary life; to lead an active life involving muscular work, the 

 level must be higher. In children, the necessity for growth renders the 

 minimum caloric intake (critical point) an improper index for deciding the 

 level of undernutrition. There are several factors which influence the 



