THE ENERGY EQUATION. 



407 



quence. The following table illustrates the dietaries of a 

 great many people living under different conditions. The fig- 

 ures are taken mainly from the compilations of Konig and 

 Atwater : 



The above results are fairly representative and show that 

 in general over 3000 Cal. per day must be provided in the 

 food. In the figures the available or net calories are calcu- 

 lated from I gm. protein or carbohydrate =4.1 Cal., i gm. 

 fat = 9.3 Cal. But many extreme results are also found in 

 the literature. For prisoners confined in cells and not work- 

 ing, for paupers in asylums, and even with laborers poorly 

 paid, the foods consumed may not yield 1500 Cal. On the 

 other hand, workmen in the American winter lumber camps, 

 who as a rule are well paid, workmen in the building trades 

 on outside work in the colder \veather, teamsters and car 

 drivers who are constantly exposed to the weather, even when 

 the work is not excessive, may consume a diet yielding over 

 4000 or even 5000 Cal. 



Special Diets. With such facts as the above in mind it is 

 not difficult to understand why nutrition with a single article 

 of food is unsatisfactory. Assume, for example, the case of 

 a diet of potatoes of which the edible portion shows in the 



