FOODS AND DIETARIES 



275 



All serve as 

 fuel and yield 

 energy in form 

 of heat and mus- 

 cular strength. 



Protein Forms tissue (mus- 



White of eggs (albumen), cles, tendon, 



curd of milk (casein), lean and probably 



meat, gluten of wheat, etc. fat). 



Fats . . ■ . Form fatty tissue. 



Fat of meat, butter, olive oil, 

 oils of corn and wheat, etc. 



Carbohydrates Transformed into 



Sugar, starch, etc. fat. 



Mineral matters (ash). . . Aid in forming bone, 

 Phosphates of Ume, potash, assist in diges- 



soda, etc. tion, aid in ab- 



sorption and in 

 other ways help 

 the body parts 

 do their work. 

 Water used as a vehicle to carry nutrients, and enters into the compo- 

 sition of living matter. 



Common Foods contain the Nutrients. — We have already 

 found in our plant study that various plant foods are rich in dif- 

 ferent nutrients, carbohydrates forming the chief nutrient in the 

 foods we call cereals, breads, cake, fleshy fruits, sugars, jellies, and 

 the like. Fats and oils are most largely found in nuts and some 

 grains. Animal foods are our chief supply of protein. White of 

 egg and lean meat are almost pure protein and water. Proteins 

 are most abundant, as we should expect, in those plants which are 

 richly supplied with nitrogen ; peas and beans, and in grains and 

 nuts. Fats, which are melted into oils at the temperature of the 

 body, are represented by the fat in meats, bacon, pork, lard, 

 butter, and vegetable oils. 



Water. — Water is, as we have seen, a valuable part of food. 

 It makes up a very high percentage of fresh fruits and vegetables ; 

 it is also present in milk and eggs, less abundant in meats and fish, 

 and is lowest in dried foods and nuts. The amount of water in a 

 given food is often a decided factor in the cost of the given food, 

 as can easily be seen by reference to the chart on page 283. 



Refuse. — Some foods bought in the market may contain a 

 certain unusable portion. This we call refuse. Examples of 



