CHAPTER XLII 

 DIET UNDER VARIOUS CONDITIONS 



IF man had to take his nutriment as one article of diet, to get 

 the necessary protein- 15 grammes of nitrogen he would require: 

 1-|- pounds of beef, or 8 pints of milk, or 3 pounds of bread, or 13 pounds 

 of potatoes,* or 60 pounds of apples. A diet consisting of 125 

 grammes of protein, 50 grammes of fat, and 500 grammes of carbo- 

 hydrate", is contained in approximately | pound prime lean meat, 

 1 pounds bread, 2 ounces butter, i pint milk, 1 pound potatoes, 

 and 1 pound oatmeal. The fat is raised to 100 grammes in the army 

 service ration i.e., for hard work in the open air of this climate. 



Sex and Age. Since man is generally bigger than woman and 

 does more muscular work, he requires the bigger intake of erfergy. 

 Men and women of equal surface area, and performing equal work, 

 require the same energy intake. A family of father, mother, and 

 four children (13, 11, 9, and 7 years) is estimated to require the 

 food of 4-5 men. Boys over 13 require a full "man value" viz., 

 3,400 calories food as purchased, the loss in cooling and absorption 

 is estimated to be 10 per cent. A woman or girl over 13 requires -8 

 man value. In old age there is a marked decrease in vitality and 

 bodily activity. Old people therefore need not, and do not, take in 

 the supply of energy required in the prime of life. Old bedridden 

 people live on a diet which probably does not yield more than 1,000 

 calories. 



Work. It has already been mentioned how the oxygen consump- 

 tion and CO 2 output are increased by muscular work. Not only do 

 the muscles perform more mechanical work, but the body generally 

 is called upon to do more ' ; physiological " work to meet their 

 needs. Either protein, fat, or carbohydrate, can yield the energy 

 required for muscular work, but since such work can be done most 

 economically at the expense of the last, a diet for hard muscular work 

 should contain an ample supply of caibohydrate with enough fat to 

 sustain the woik between meals. Carbohydrate is used first, while 

 fat, more slowly digested and absorbed, is used later. 



Temperament. Some people are by temperament vivacious and 

 active, others are more phlegmatic and quiet. The latter will expend 

 less energy as muscular work than the former, and therefore require 



* Three to four grammes of nitrogen seem to suffice on a potato diet. 



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