u8 GENERAL SCIENCE 



Because of the great amount of heat produced by fat 

 when it is oxidized, the people living in cold countries, 

 as the Eskimos in the North, must eat large quantities 

 of fat in order to keep warm. They become accustomed 

 to digesting large quantities of fat because their bodies 

 need it. People living in a temperate climate like that 

 of the northern United States usually consume more 

 fats or fatty foods during the winter season in order that 

 they may not suffer so much from the cold weather. In 

 summer or in warm climates people naturally do not 

 eat much fatty food. They do not have an appetite 

 for such food, since the great amount of heat produced 

 by the oxidation of fats is not needed during that time 

 of the year. The appetite, if not perverted or spoiled 

 by improper eating, is a comparatively sure guide in 

 determining how much fatty food to eat. 



(c) Proteins. Proteins are foods which contain nitro- 

 gen and are sometimes called nitrogenous foods. The 

 elements composing protein are hydrogen, nitrogen, car- 

 bon, oxygen, and some sulphur. Proteins are the building 

 foods. They form about 80 per cent of the weight of 

 the muscles of the body and are present in all the other 

 tissues. When not enough carbohydrates and fats are 

 eaten to produce the heat necessary to keep the body 

 warm, the proteins are oxidized to make heat. But 

 when proteins are oxidized, not only carbon dioxide is 

 produced, but nitrogenous wastes also. The nitrogenous 

 wastes are very poisonous to the body. They are taken 

 from the body by the kidneys and the sweat glands, and 

 these organs especially the kidneys may become 

 diseased in throwing off the waste produced by the oxida- 

 tion of proteins. For this reason it is best to eat just 

 enough carbohydrates and fats to produce the heat 



