DIETETICS. 849 



although it is not advisable to eliminate either of these foodstuffs 

 entirely from the diet. The fact that within certain limits fats 

 and carbohydrates may be substituted for each other is illustrated 

 in a general way by the different diets recommended by various 

 physiologists, as follows: 



AVERAGE DIETS AND THEIR HEAT VALUES. 



MOLESCHOTT. RANKE. VoiT. 



CALORIES. CALORIES. CALORIES. 



Protein.. ..130 gms. .. 533,(X)6 100 gms, ... 410,000 118 gms. . . 483,000 



Fats 40 " ... 372,000 100 " ... 930,000 56 " ... 520,800 



Carbohydrates. 550 " ...2,275,000 240 ' . . . 984,000 500 ' ...2,050,000 



2,980,000 2,324,000 3,053,800 



FORSTER. ATWATER. 



CALORIES. CALORIES. 



Proteid 131 gins. . . . 567,100 125 gms. . . 512,500 



Fats 68 " ... 632,400 125 " ...1,172,500 



Carbohydrates. 494 " ...1,825,400 400 ' . ..1,640,000 



2,024,900 3,325,000 



The average heat value of these diets is equal to 2,741,540 calo- 

 ries. In round numbers it is usually estimated that the diet should 

 furnish daily 2,400,000 calories for an individual weighing 60 kgms., 

 or about 40,000 calories per kgm. of body -weight. It will be noticed 

 that in all cases the greatest portion of this energy is obtained from 

 the carbohydrate food, which, on account of its economy, its abun- 

 dance, and its ease of digestion and oxidation in the body, consti- 

 tutes the bulk of our diet. In cases of excessive muscular work 

 the food eaten may supply more than twice the average heat value 

 given above. Thus, Atwater and Sherman * estimate that in a six- 

 day bicycle race by professionals the heat value of the food for the 

 different participants varied from 4,770,000 to 6,095,000 calories. 

 Chittenden, in the work previously referred to,f has raised the 

 question whether the heat value of the diet ordinarily employed 

 is unnecessarily high. In his own case he found that the body 

 could be well nourished on a diet containing a total heat value of 

 only 1,600,000 calories or 28,000 calories per kgm. of body -weight 

 instead of 40,000 calories. The diet in this case, it will be remem- 

 bered, contained only 36 to 40 gms. of protein in place of the 100 to 

 130 gms. recommended in the diets mentioned above. The ques- 

 tion thus raised is one that must be decided by actual experience. 

 Mankind is guided and has been guided in all times by the control 

 of the appetite, using this term in a general sense to designate the 

 conscious desire for food, and also the desire, more or less clearly 



* Bulletin 98, United States Department of Agriculture, 1901. 

 t Chittenden, u Physiological Economy in Nutrition, " 1905. 

 54 



