144 



FOODS 



(91 X 9.3) 846.30 calories, or a total of 847.53 calories from 100 gm. of 

 butter. This is more than one-third as much energy as was afforded 

 by the bread, ten times as heavy. The following table, compiled by 

 Atwater, gives a fair estimate of the calorie-needs of men performing 

 various degrees of labor. 



DIETETIC NEEDS FOR VARIOUS DEGREES OF LABOR. 



We shall have a little more discussion of the quantitative adaptation 

 of diets later on (p. 151). Even the last two diets summarized in the 

 above table are not the extremes of actual diets in the overcivilized 

 countries of Europe and of America. Playfair reported, about thirty- 

 five years ago, a London sewing-girl with weekly earnings of three shill- 

 ings ninepence, who subsisted on 53 gm. of proteid, 33 gm. of fat, and 

 316 gm. of carbohydrate, a diet theoretically worth only 1820 calories. 

 The physiological conditions which made life on so little fuel possible 

 are obvious. The individual was a female, doubtless not tall, certainly 

 very thin, with a relatively small amount, therefore, of tissue-waste. 

 Her labor had in it almost a minimum of both bodily and mental 

 exercise, and was carried on almost if not quite wholly indoors. It was 

 done doubtless in that spiritless and feeble way characteristic of any 

 machine, natural or artificial, with little power behind it. At the other 

 extreme, Atwater found in Cambridge, Massachusetts, brickmakers who 

 daily consumed 180 gm. of proteid, 365 gm. fat, and 1150 gm. of 

 carbohydrate, giving altogether 8848 calories of energy. These are 

 indeed extremes that of the little seamstress almost a starvation, 

 indoor diet barely enough to keep body and soul together, while that 

 of the brickmakers is the almost gluttonous diet of well-paid workmen, 

 in one of the most laborious of outdoor trades. 



Using the combustion values of proteid, fat, and carbohydrate already 

 given, the average food -requirements as estimated by seven older authori- 

 ties, give the following averages: Of dry proteid, according to these older 

 figures, about 121 gm. is required, of dry fat about 59 gm., and of dry 

 carbohydrate 510 gm. To these numbers should be added 30 gm. of 

 inorganic salts and 3 liters of water. The recent work by Chittenden 

 and some others makes it fairly probable that these amounts are exces- 

 sive as a grand average requirement for the average adult human being. 

 It has lately been claimed that man does not masticate his food suffi- 



