938 NUTRITION AND HEAT REGULATION. 



The figures that are used, therefore, in estimating the heat value 

 of our foodstuffs are : 



1 gm. protein = 4100 calories (4.1 C.). 



1 gm. carbohydrate (starch) = 4100 calories (4.1 C.). 

 1 gm. fat = 9305 calories (9.3 C.). 



Making use of these values, it is obvious that we can calculate the 

 total heat value of any given diet. If we analyze the food for its 

 composition in the three principal foodstuffs we may determine how 

 many calories will be furnished to the body. In many of the tables 

 published to show the composition of the different foods figures are 

 given also to express their heat value or potential energy, on the 

 belief that, for the most part, our food is used as fuel to supply 

 energy to the body. These values for some of our ordinary foods 

 are as follows : * 



PROTEIN. FAT. CARBOHY- ASH. IN CALORIES 

 PRATE. p ER PoUND> 



Beefsteak, porterhouse 19.1 17.9 0.8 1110 



Beefsteak, round (lean) 20.2 2.4 1.2 475 



Corned beef (canned) 26.3 18.7 4.0 1280 



Veal, leg (lean) 19.4 3.7 1.1 520 



Veal liver 19.0 5.3 1.3 575 



Mutton, leg (lean) 16.5 10.3 0.9 740 



Pork, ham (fresh, lean) 24.8 14.2 1.3 1060 



Pork chops, medium fat 13.4 24.2 0.8 1270 



Chicken (fowl) 13.7 12.3 0.7 775 



Shad 9.4 4.8 .... 0.7 380 



Shad roe 20.9 3.8 2.6 1.5 600 



Eggs... 11.7 10.7 0.7 680 



Milk 3.3 4.0 5.0 0.7 325 



Oatmeal 16.1 7.2 67.5 1.9 1860 



Rice : 8.0 0.3 79.0 0.4 1630 



Wheat flour (entire wheat) 13.8 1.9 71.9 1.0 1675 



Green peas 7.0 0.5 16.9 1.0 465 



Potatoes (raw) 2.2 0.1 18.4 1.0 385 



Spinach 2.1 0.3 3.2 2.1 110 



Tomatoes 0.9 0.4 3.9 0.5 105 



Apples 0.4 0.5 14.2 0.3 290 



Bananas 1.3 0.6 22.0 0.8 460 



It must be borne in mind, however, that .the entire nutritional 

 value of a food is not expressed in its heat value. Some of our 

 food material the green foods and fruits, for example are useful 

 and in a measure essential because of their salts and organic acids, 

 in spite of the fact that they contain but little energy that can 

 be utilized by the body. Moreover recent work, already referred 

 to (p. 901), makes it increasingly probable that the different 

 proteins or even the different carbohydrates or fats may be found 

 to have each a specific influence upon metabolism. And, lastly, 

 specific substances may be found in the foods (vitamines), which 

 in some as yet undetermined way are important or essential to 



* Selected from Atwater and Bryant, Bulletin 28 (revised edition), United 

 States Department of Agriculture, 1889. 



