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FIRST YEAR SCIENCE 



oils. The common foods that consist largely of proteins 

 are lean meat, cheese, eggs, beans, and peas. Those 

 largely composed of carbohydrates are most cereals, vege- 

 tables and fruits. The fats are butter, pork, nuts and 

 chocolate. Milk contains all three of these compounds 

 in approximately the proportion needed by the body. 



Careful experiment 

 has shown that the aver- 

 age, full-grown American 

 needs each day two to 

 three ounces of proteins, 

 about four ounces of fats 

 and a pound of carbo- 

 hydrates. The weight 

 of food eaten, however, 

 is very much greater than 

 this, as all foods are com- 

 posed largely of water. 

 The proteins are needed 

 for growth and repair, 

 since the living part of 

 the cells, the protoplasm, 

 is composed of proteins. 

 The rest of the food furnishes energy. 



Until recently, it was thought that a great deal of meat 

 was necessary to furnish the energy needed for hard mus- 

 cular work. But now investigation has shown that this 

 energy can better be supplied by other foods and that eat- 

 ing too much meat is not only needlessly expensive but 

 bad for the system. The staple food of northern Africa 

 and southwestern Asia is the date palm, which is admi- 

 rable for hot climates. In cold regions where the body 

 requires great energy to keep up its heat, much fat is 

 eaten and sugar, if procurable. The exact kind of food 



A DATE PALM. 



