844 



XIV. NUTRITIONAL VALUE OF FATS 



great, namely, 244 calories. If fat can normally reduce the loss of heat 

 due to specific dynamic action to such an extent in animals other than the 

 rat it should result in a greater efficiency of utilization of fat diets in other 

 species also. As far as the author can see, there is no reason why this 

 associated dynamic action should be confined to the rat. Figure 2 gives 

 a graphic representation of the results on associative dynamic action ob- 

 tained by Forbes and Swift. -^ 



BEEF PROTEIN 

 1000 



LARD 

 1000 



160 



CERELOSE 

 BEEF PROTEIN 



EXPER. 238 



432 

 568 



COMR 272 



CERELOSE 

 LARD 



495 

 505 



EXPER. 119 



COMR 183 



EXPER. 113 



COMR 244 



EXPER. 181 



COMR 231 



Fig. 2. The dynamic effects per 1000 calories of gross energy of nutrients as affected 

 by nutrient combinations. 2« (From original of Fig. 2, E. B. Forbes, R. W. Swift, J. Nu- 

 trition, 27, 4^-1 (194-i).) 



Table 1 indicates the breakdown as to the source of the energ}^ the 

 metabolizable calories and the output of energy in the groups of rats re- 

 ceiving 2%, 5%, 10%, or 30% of the diet in the form of fat.^^ 



It is evident from an inspection of Table 1 that the de(a'eased expenditure 

 of total calories which occurs when fat replaces carbohydrate in the iso- 

 caloric diets is sufficient to account for the greater efficiency of growth 

 observed when high -fat diets are utilized, as compared with that when 



2" 11. \V. Swift and A. Black, J. Am. Oil Chcnnata' Aasoc, 26, 171-1 7(j (19-4'J). 



