CARBOHYDRATES AND FATS. 831 



of cold regions choose a diet rich in fat. (3) It is a protein saver. 

 Like the carbohydrate food, its oxidation protects the protein from 

 consumption. In starvation, therefore, the amount of protein 

 destroyed daily is smaller as long as any fat remains, and, under 

 ordinary conditions of life, the larger the amount of fat in the diet, 

 the less the amount of protein necessary to maintain the body 

 in nitrogen equilibrium. Experiments show that in this respect 

 the fat is not so effective as an equivalent amount of carbohydrate 

 food. The difference is referable to the greater difficulty of oxida- 

 tion of the fatty material, and, perhaps, also to the fact that the 

 necessary sugar which the body requires, even in starvation, is 

 obtained largely from the proteins when carbohydrates are lacking 

 in the diet. 



