8o SCIENCE OF HOME AND COMMUNITY 



More calories in proportion to the weight are needed for 

 children than for adults. For the two-year-old child about 

 40 calories per pound are required. This number gradually 

 decreases to about 20 at the age of 16. 



In old age the number of calories needed is less than during 

 middle age. This decrease runs from 10 per cent at 60 years 

 of age to 30 per cent for those over 80 years of age. 



Protein requirements. Having noted the heat require- 

 ments of the body, we may next ask how much protein food 

 the body needs. While protein as well as fats and carbo- 

 hydrates furnishes energy, it is better to meet these heat 

 requirements through the use of fats and carbohydrates, 

 and to provide protein only for the repair of the body tissues. 

 We have seen that the calorie requirement of the body de- 

 pends on weight, age, and activity. The protein require- 

 ment depends on weight and age, but not on activity. A 

 man when he is doing severe muscular work has the same 

 protein requirements as when he is doing light work. 



While there is quite general agreement among authorities 

 regarding the number of calories needed by the body, there 

 is a difference of opinion regarding the amount of protein 

 needed. There are two schools, one favoring a low protein 

 diet, and the other favoring a high protein diet. The stand- 

 ard set by the first school for a man of 150 pounds' weight 

 is 60 grams (about 2 ounces) daily : the standard set by the 

 second school is about 100 grams (about 3-^ ounces). 



Chittenden's experiments. Professor Chittenden of Yale 

 University is an exponent of the first school. During 1903 

 and 1904 he carried on a series 'of experiments to test the 

 effect of a low protein diet. He selected for this purpose 

 men representing a variety of occupations : soldiers, college 

 athletes, and college professors. The experiment lasted for 

 6 months. During the first month the foods were gradually 

 changed so as to include smaller quantities of proteins, until 

 during the last 5 months the diet contained less than half 



