of "shares" of energy be proportionately less than the number of "shares" 

 of each of the other essential nutrients. 



Shares in Foods' With this device of "shares" it is easy to plot an indi- 

 vidual's total needs and to plan to meet those needs with shares of food. 

 The table on page 131 shows the contributions of common foods to the diet 

 in relation to their energy value. Note that in many cases a share of energy 

 corresponds roughly to a serving we commonly take. By representing with 

 bar graphs the shares of each of these dietary essentials, one can quickly 

 visualize which foods are rich in energy, or mineral, or ascorbic acid, and 

 so on (see pages 126, 127). 



Lettuce, spinach, and other fresh vegetables and fruits contain a high 

 percentage of water; they therefore yield relatively little energy per pound. 

 On the other hand, butter and other fats are extremely rich sources of energy 

 (see footnote, p. 125). Sugar, candy, and other sweets yield much energy 

 and little else. Milk, cheese, meat, fish, eggs, peas and beans are rich 

 sources of proteins. The mineral content of milk, cheese, eggs, and various 

 fruits and vegetables is high. Some foods are rich in one vitamin and poor 

 in other vitamins. In general, milk, eggs, liver, and various fruits and vege- 

 tables are high in vitamin content. The foods arbitrarily listed in the table, 

 p. 131, illustrate the shares present in different kinds of foods. 



In Brief 



The basic needs of the body vary primarily with the rate of growth and 

 with the amount of heat lost from the body surface. 



Above minimum, or basic, energy expenditure the activities determine 

 the energy required by an individual from hour to hour. 



The energy expenditures of the body are measured in heat units, Calories, 

 by various types of calorimeters. 



The basal metabolism of a person is his rate of energy expenditure when 

 he is awake, relaxed and lying still, at least twelve hours after the last meal. 



Because children vary in size, in rates of growth, and in activity, their 

 energy requirements at any given age vary widely. 



The total energy requirement of a day-laborer doing heavy work is ap- 

 proximately twice that of a similar person engaged in clerical work. 



One can continue for a long time on a deficient diet without realizing it, 

 but in the meantime injuries accumulate. It is therefore important to acquire 

 tastes and practices guided by reliable knowledge of food needs. 



Milk and milk products, eggs, and fruits and vegetables are considered 

 "protective" foods because of the minerals and vitamins they contain. 



iSee No. 6, p. 136. 

 134 



