308 THE FOODS WE EAT 



interesting experiments were carried out by some school 

 children in Texas. They chose six rats of the same size 

 and weight from the same litter, and tried feeding them 

 on the same ration of corn meal, water, and green food, 

 but two of the rats were given milk in addition while two 

 others had chile, another candy, and another a soft drink 

 added to their diet. The children found that "The rats 

 given milk grew to be larger, had finer hair, brighter eyes, 

 were better natured, and were more active" than those 

 which did not have milk. It is experiments like these 

 that give us some of our information about the kinds of 

 foods that are best for growing boys and girls. 



We know that our bodies use food not only to release 

 energy so that we can do work, but also they help the body 

 to grow. Rather recently a third use of foods, that of 

 protecting and regulating the body, has been found. We 

 will later learn something about the kinds of food that do 

 these things. 



If foods are oxidized in the body, the amount of energy 

 given off ought to depend on the kind and amount of food 

 that is eaten. This, in a general way, is true. People 

 who do hard physical work should eat more food, and food 

 that has greater fuel value, than those who lead inactive 

 lives. The boy or girl who plays hard needs more fuel 

 food than another boy or girl of the same age and weight 

 who stays indoors reading. People in the arctic region, 

 where the cold makes demands on the system and where 

 hard work has to be done in order to gain a scanty living, 

 consume much more heat-producing food than do people 

 living in the tropics. In our own country we eat more 

 food and more heat-producing foods in the winter than 

 we do in the summer. We have heard of people fasting 

 for long periods of time. In order to do this they dress 

 warmly or go to bed so as to prevent the body heat from 

 escaping. Since they do not exercise, very little energy 



