56 HOUSEHOLD AND HEALTH PEOBLEMS 



67. Food substances and their percentages found in 

 different foods are about as follows : 



68. The farm hand requires daily about 4^ oz. of proteid, 

 4J oz. of fat, and 16 oz. of carbohydrates. These food elements 

 are found in widely different ratios in different foods. By a 

 chemical analysis of a food it is possible to find the approxi- 

 mate quantity of that food which must be eaten to furnish the 

 required amount of proteid, fat, or carbohydrate for a day. 



EXAMPLE. Wheat bread contains about 8.9% of digestible proteid. 

 How much bread will be required to produce 4 \ oz. of proteid ? 



SOLUTION. 4^ oz. of proteid is the amount required. 

 8.9% of the wheat bread is proteid. 

 4 oz. equals 8.9% of the required amount of bread. 



The amount of proteid required divided by the per cent of the 

 analysis expressed as a decimal gives the quantity of bread. 

 4.5 oz. -4- .089 = 47 oz. 



