336 



FOODS AND DIETARIES 



minerals 



The composition of a 

 bottle of milk. 

 Why is it con- 

 sidered a good 

 food? 



mineral matter being also present. For these reasons, milk is exten- 

 sively used as a food for children, as it combines food material 

 for the forming of protoplasm with mineral matter for the building 

 of bone. Some vegetables (for example, peas 

 and beans) contain the nitrogenous material 

 needed for protoplasm formation in consider- 

 able proportions, but in a less digestible form 

 than is found in some other foods. Vege- 

 tarians, then, are correct in theory when 

 they state that a diet of vegetables may 

 contain every- 

 thing neces- 

 sary to sustain 

 life. But a 

 mixed diet is 

 healthier. A 

 purely vege- 

 table diet 



contains much waste material, 

 such as the cellulose forming the 

 walls of the plant cells, which 

 is indigestible. The Japanese 



army ration consists almost entirely of rice. A recent report by 

 their surgeon-general intimates that the diminutive stature of 

 the Japanese may, in some part at least, be due to this diet. 



The Relation of Work to Diet. It has been shown experimentally 

 that a man doing hard, muscular work needs more food than a person 

 doing light work. The mere exercise gives the individual a hearty ap- 

 petite ; he eats more and needs more of all kinds of food than a man or 

 boy doing light work. Especially is it true that the person of sedentary 

 habits, who does brain work, should be careful to eat less food and food 

 that will digest easily. His proteid food should also be reduced. Rich 

 or hearty foods may be left for the man who is doing hard manual labor 

 out of doors, for any extra work put on the digestive organs takes away 

 just so much the ability of the brain to do its work. 



The Relation of Environment to Diet. We are all aware of the fact 

 that the body seems to crave heartier food in winter than in summer. 

 The temperature of the body is maintained at 98^ in winter as in sum- 

 mer, but much more heat is lost from the body in the cold weather. Hence 

 feeding in winter should be for the purpose of maintaining our fuel sup- 



Three portions of foods, each of which 

 furnishes about the same amount of 

 nourishment. 



