28 BULLETIN" 468, IT. S. DEPARTMENT OE AGRICULTURE. 



wholesome, palatable, and useful food, and can be prepared for the 

 table in many acceptable forms without undue labor or fuel. 



The starchy roots are important in nutrition as sources of energy. 

 Figure 7 shows in graphic form the energy value of some of the more 

 common of such vegetables. 



As the diagram shows, the energy value varies from about 400 to 

 600 calories per pound. In general, the drier the root the higher the 

 energy value, which means that potatoes, for instance, which have 

 been harvested and dried out may have an energy value considerably 

 higher than the value here cited as an average. 



CONCLUSION. 



All these starchy tubers and roots — potato, sweet potato, Jerusalem 

 artichoke, cassava, yam, dasheen, yautia, and taro — yield the body 

 little protein to supply nitrogen needed for building body tissue 

 and little energy-producing fat, but on the other hand their fine- 

 grained starch and other carbohydrates supply easily digested energ}^- 

 yielding nutritive material and small quantities of valuable min- 

 eral matters which help to build the bones and are useful for other 

 physiological purposes. Thanks to the ease with which most of 

 them are cultivated, they are among the cheaper of our vegetables, 

 while their usually mild flavors and the variety of ways in which 

 they may be prepared make it possible to serve them in many com- 

 binations. They merit their extensive use because they make health- 

 ful supplements to other classes of food found in the usual mixed 

 diet, and because they are economical and agreeable sources of body 

 energy. 



