306 THE PUTTING ON OF FAT 



that of the oxidation of fat. Carbohydrate raises the meta- 

 bolism double as much as fat, and proteid when fed in large 

 amounts may increase it 90 per cent., as so much rapidly 

 undergoes chemical cleavage. 



THE PUTTING ON OF FAT 



Flesh cannot be put on by over-feeding proteid, unless the 

 diet be accompanied by bodily effort, with the exception of con- 

 valescents and children. In such cases N will be retained even 

 on an insufficient diet, and much more so on a rich one. The de- 

 posit of fat, on the other hand, is directly dependent on the amount 

 of food assimilated. Fat can be put on (1) by increased food, (2) 

 by lessened expenditure of energy, (3) by these two causes acting 

 together, and this is the common case. 



A man requires a daily diet equivalent to about 



30 Cal. per kg. of body weight when resting in bed. 

 40-45 Cal. per kg. of body weight when doing moderate work. 

 45-50 Cal. per kg. of body weight when doing strenuous work. 

 (1 grm. proteid = 4-1 Cal. 1 grm. fat = 9-3 Cal. 1 grm. Carb. = 4'l Cal.) 



About T3-1-5 grm. proteid per kg. must be in the food e.g. 

 a man of 70 kg. requires 90-115 grm. proteid = 370-470 Cal. 

 Chittenden says only half the amount of proteid given in ordinary 

 diet-tables is necessary. He has kept soldiers in full vigour and 

 perfect health on this amount, increasing the carbohydrates pro- 

 portionately. The lean require relatively more proteid and the fat 

 less, because the proportionate weight of living active cells is 

 greater in the former. The tall lean man also requires more 

 Calories than the short fat man, because in the former the surface 

 exposure in proportion to body mass is much greater. 



FATTENING BY OVER-EATING 



In the matter of fattening the whole question is one of the 

 balance of intake and output of energy. The popular idea that 

 potatoes are more fattening than bread, bread-crumb than crust, 

 beer than wine, is baseless ; the only thing of moment is t/he 

 potential energy of the food. 



