16 



An ounce of fat measured by this " heat " scale yields more than twice 

 as much heat, and therefore energy, as do similar amounts of protein or 

 carbohydrate. 



WHITE OF EGG IS PRACTICALLY PURE PROTEIN. 



If the white of an ordinary-sized egg is burned with proper precautions, 

 it yields 16 calories. 



SUGAR IS PRACTICALLY PURE CARBON. 



If a small lump be burned, of the same weight as the white of egg, it 

 also measures 16 calories. 



OLIVE-OIL IS PRACTICALLY PURE OIL OR FAT. 



If a corresponding weight of olive-oil be burned (about a thimbleful) , it 

 would yield nearly 40 calories; that is more than twice the amount of heat 

 measured in the other two cases. 



It is a sound instinct, then, which impels us in cold weather or when 

 doing hard manual work to eat more fat-containing foods than when sitting 

 quietly at a desk or worktable; or when "melting" with heat at midsummer. 

 A man doing hard, muscular work needs to eat daily food which will furnish 

 him with about 3,000 calories. 



TABLE OF NUTRITIVE VALUE OF SOME COMMON FOODSTUFFS. 



A LUMP OF BLUBBER AFFORDS AS KEEN PLEASURE TO AN 

 ESQUIMAUX CHILD 



as does a stick of chocolate to one of our own small folk or a banana to a 

 little blackamoor in the Tropics, because it lives in an intensely cold climate 

 and its body-furnace calls for more vigorous stoking. How is it, then, that 

 few people can take fat in any quantity, if it is so useful as a source of lu-.-it 

 and energy to the body? 



The answer to this inquiry is found in the fact that 



FAT IS MORE DIFFICULT TO DIGEST, 



and takes longer to undergo the series of changes necessary before it yields 

 energy to the body, than is the case with foods containing protein or carbo- 

 hydrates; so we find that mountain-climbers, harvesters, or men on a long 

 march, eat, by preference, chocolate, preserves, or molasses in large quantities ; 

 because sugar undergoes more rapid combustion in the liver and muscles than 

 fat does; thus the energy it yields is more quickly available to meet any 

 unusual call. 



