A STUDY OF FOODS AND DIETARY 355 



Protein 2562 greater calories per pound 



Carbohydrate 1860 greater calories per pound 



Fat 4286 greater calories per pound 



But the body does not realize the full heat value of the food 

 principles when they are oxidized in the body. This is because 

 of incomplete digestion and incomplete oxidation. The follow- 

 ing is the net value in heat units of the above to the body: 



Protein 1815 greater calories per pound 



Carbohydrate 1815 greater calories per pound 



Fat 4084 greater calories per pound 



It will thus be observed that protein and carbohydrate are of 

 equal value to the body as producers of energy, while fat pro- 

 duces about 2 J times as much energy. It is a well-known fact 

 that fatty foods are greater heat producers than other kinds. 

 Inhabitants of cold climates consume and relish large quanti- 

 ties of fat. Most of us have a better appetite for fat in the 

 winter than in the summer. Why? 



394. Bread and Butter ; Pork and Beans. These are well- 

 known combinations of food. Why are these foods thus 

 combined? It will be observed that bread is composed of 9.2 

 per cent, protein, 1.3 per cent, fat, and 53.1 per cent, carbo- 

 hydrate. It is therefore rather poor in fat. Butter on the 

 other hand is rich in fat, so that a thin coat of butter on a slice 

 of bread supplies the deficiency of fat in the bread. Explain 

 why the combination of fat pork and beans is better than 

 either one alone. What combination would you suggest 

 with eggs? Why do we relish cheese with bread or crackers? 

 Why do we combine meat and potatoes? Why combine milk, 

 eggs, and sugar in a custard? 



395. Food for a Day. Let us consider the daily menu of a 

 man at moderately active muscular labor. Suppose we 

 consider that he eats the following amounts of food : Bread, 

 1 lb.; round steak, J^ lb.; bacon, J4 lb.; milk, 1 lb.; potatoes, 

 1 lb.; butter, 1 oz.; and sugar, J/ lb. What amounts of 

 energy and of protein will such a menu furnish him? Our 



