OCCURRENCE AND CONSEQUENCES OF UNDER-NUTRITION 59 



less than the requirement for maintenance, fat is always lost; when it is 

 greater than the requirement for maintenance fat is always accumulated. In 

 the former case we speak of under-nutrition, in the latter case of over- 

 nutrition. 



Although I shall be repeating what is known to most readers, it is neces- 

 sary to devote a few lines to the definitions of food necessary for maintenance, 

 of over-nutrition, and of under-nutrition. 



In proportion to the requirement of the cells, according to the amount of 

 work required of them externally and internally in heat production, etc., the 

 body arranges the use of material for combustion. When the combustion 

 value of the food is equal to the demand, the equilibrium of metabolism in 

 the body is preserved. The amount of food which is necessary for this we 

 call " food necessary for maintenance." Most normal persons, if left to them- 

 selves and following their own inclinations, usually take neither more nor 

 less food than is necessary for maintenance; variations in this balance of 

 nutrition may occur, but tlie deficiency of one day is made up the next. Con- 

 sequently it is the rule that normal adults remain for years and decades at 

 about the same weight. The proportion of food which is necessary for the 

 equilibrium of metabolism, calculated per day and for each kilo of the body- 

 weight, must have a combustion value of from thirty to thirty-five calories in 

 complete rest (in bed), thirty-five to forty calories with light exercise, forty 

 to forty-five calories with moderate exercise, and forty-five to sixty calories in 

 exhausting muscular labor. 



For children these figures are to be raised about one-third, for the aged 

 they are to be lowered about one-fourth. There are no decided differences 

 between males and females. These figures relate to a " moderate condition 

 of nutrition " ; in the obese they are from twenty to twenty-five per cent, 

 lower, in very thin persons they are just as much higher, for while fat in- 

 creases the body-weight it takes no part in metabolism. This ratio will enable 

 us to calculate the amount of food necessary in the individual case with suffi- 

 cient exactness for practical purposes. 



3. OCCURRENCE AND CONSEQUENCES OF UNDER-NUTRITION 



As soon as the supply of -food (i. e., its combustion value) falls below that 

 required for maintenance we have a state of hyponutrition. The imder-nour- 

 ished body does not accommodate its combustion processes to a lower scale — 

 except perhaps in the most extreme marasmus and in the death agony. When 

 the supply is less than the requirement, it lives upon its own body substance. 

 In the obese, as we have seen, this process may be limited to the adipose 

 tissue while the albumin, that is, the muscle, is preserved. In normal and 

 mal-nutrition, however, apart from exceptional cases (in convalescence after 

 acute diseases, or after periods of hunger), the supply of albumin in the body 

 may also be slowly consumed, and the person not only loses fat but becomes 

 weaker in muscle. We rarely resort to systematic under-nutrition except in 

 -the treatment of obesity. Whether or not treatment for obesity is indicated 

 does not depend wholly upon the degree of corpulence, but also upon many 



