436 



SMITH S INTERMEDIATE CHEMISTRY 



Normal Diet. There is much uncertainty, as yet, in regard 

 to the best choice of foods, in respect to the exact distribution in 

 kind and quantity. We know, however, that life cannot be 

 maintained on one kind (say, sugar or gelatine) alone. A mixed 

 diet is necessary. In general, it appears that 100 g. of proteins 

 (giving 4 X 100 Cal.) per day, and a sufficient amount of other 

 foods to bring the total fuel value up to 2200 Cal. per day, is 

 sufficient for a person leading a strictly sedentary life. For work 

 involving physical exercise, larger values, up to about 3800 Cal., 

 are required. 



From the data given in the table (p. 429) the fuel value of 100 

 g. of each kind of food can easily be calculated. 



Fuel Values and Prices of Foods. If the current prices are 

 considered, one can also readily calculate the fuel value obtainable 

 for a given sum of money invested in each kind of food. Thus: 

 lean beefsteak contains 22.1 per cent of protein, or 0.221 pounds 

 per pound of meat. The fuel value of this protein is 0.221 X 1800, 

 or 398 Cal. per pound. 



* The prices vary gr atly with the quality, the season of the year, the demand, the supply, etc. 



Vitamins. A diet may be carefully balanced with respect 

 to carbohydrates, fats and proteins, and yet lead to malnutrition 



