522 NUTRITION. 



table carbohydrate into dear animal fat. Further aids in fattening may be 

 found in providing repose for the body of such a kind that, while sufficient 

 energy is expended to secure adequate digestion and absorption of food, all 

 causes leading to an increase of metabolism by which energy is set free and 

 leaves the body are avoided as much as possible. 



To avoid fat rather than to increase it is often an object of human care. 

 This may be effected by diminishing fats and carbohydrates, but also, in a 

 very marked manner, by relatively increasing the proteids. Proteid food, 

 as we have seen, augments the whole metabolism of the body, hurrying on 

 the destruction not only of proteid but of carbon food ; and a tendency to 

 corpulency may be counteracted by a diet in which fats and carbohydrates 

 are much restricted, and proteids are largely increased. When, as in what 

 is known as the Banting method, the diet is almost exclusively proteid, the 

 nitrogenous overwork entails dangers on organisms which do not possess the 

 power of ridding themselves freely of the large amount of nitrogenous waste 

 which such a diet produces. A less severe method in which the fats and 

 carbohydrates are diminished only, not entirely done away with, and the 

 proteids only moderately increased, is less open to objection ; and such a diet, 

 assisted by other hygienic conditions, has proved successful. 



An increase of daily food, largely proteid in nature, given under cir- 

 cumstances such as a large amount of passive exercise and skin stimulation, 

 known as " massage," which will not only favor digestion but also promote 

 metabolism in general, may be given with favorable results. In this way 

 an enormous metabolism may be excited, and yet so carried on that the 

 body gains both in flesh and in fat. Thus, in one case, the patient with an 

 initial weight of 45 kilos, and a daily nitrogenous metabolism calculated as 

 28 grms. proteid, reached in the course of about fifty days a weight of 60 

 kilos, the daily nitrogenous metabolism being raised on one occasion to 182 

 grms. proteid/ with an average on the whole period of 150 grms. During 

 the treatment no less than 8420 grms. of proteid were taken as food. 



470. With regard to labor, since, as we have seen, the energy expended 

 as work done is not taken out of and away from the amount set free as heat, 

 the two forms of energy being so related that an increase of work done is 

 accompanied by a greater or less increase of heat set free, it is obvious that 

 a man who is doing a hard day's muscular work needs a larger income of 

 energy for the day than does an idle man. What we have learnt concerning 

 muscular metabolism further shows us that the additional energy needed is 

 not necessarily to be supplied by an increase in the proteid components of 

 the diet ; the energy of muscular contraction does not come, as was once 

 thought, from proteid metabolism ( 443). The fact that it is the carbon 

 metabolism which is augmented in muscular work may suggest that the 

 extra food for extra work should be exclusively carbon compounds ; and if, 

 as seems probable, the carbohydrates are more readily and directly available 

 for the functional metabolism of muscle than are the fats, we might be further 

 led to recommend an increase in carbohydrates to form a diet especially suited 

 for labor. But several considerations should make us hesitate before we come 

 to such a conclusion. A muscle is not a machine within the body which can 

 be loaded and fired off irrespective of the rest of the body. In the perform- 

 ance of muscular labor, the condition of the muscle, the amount of energy 

 available in the muscle itself, is of course of prime importance ; but, and 

 this perhaps especially holds good in severe labor, of great importance also, 

 we might almost say of no less importance, is, as we have urged ( 333), the 

 power of the body as a whole to avail itself of the energy latent in the mus- 

 cle. The power of doing work hangs not on the muscle alone, but on the 

 heart, the lunjis, the nervous system, and, indeed, on the whole body. It is 



