e part of ancient scientists. It is now
known that animal heat is derived from the food we eat by means of a
peculiar process of vital oxidation--effected in the presence of
oxygen--by the action of water and enzymes upon the food elements
absorbed by the living cell. This process of oxidation liberates the
heat and energy stored by the sun in the food, and thus the body is
kept warm by this constant combustion of the digested foodstuffs. The
starches and sugars, together with the fats, represent food elements
which serve as the body's fuel. By this means we are able to maintain
a constant body temperature of almost one hundred degrees.

The average human body produces enough heat every hour to raise two
and one-half pounds of water from the freezing point to the boiling
point. This is equivalent to boiling about seven gallons of ice-water
every twenty-four hours. Differently expressed, the body gives off
each hour the same amount of heat as a foot and a half of two-inch
steam coil. This is the same amount of heat which would be produced by
burning about two-thirds of a pound of coal.

FUEL VALUE OF FOODS

Expressed in terms of English weight, the fuel value of the three
different food elements would be:

1 ounce of carbohydrates 127.5 calories
1 ounce of proteins 127.5 "
1 ounce of fat 289.2 "

It will be observed that fat contains more than twice as much heat as
the carbohydrates. This is due to the fact that fat contains more
carbon than either starch or sugar. Next to fats, starches and sugars
are the most important fuel elements. Protein is a very extravagant
form of food for fuel purposes. Proteins are the most expensive
elements of human food; they are incompletely burned in the body, and
inasmuch as they leave behind distressing and disease-producing ashes,
it is clearly evident that only sufficient amount of proteins should
be eaten each day to supply the demand of the body for repairs. We
should depend more largely upon the carbohydrates and fats for heat
and energy.

A large part of our food is required to furnish heat to take the place
of that lost by radiation from the skin, and this is why children
require more food than adults--they have a larger skin surface in
proportion to their weight, and therefore lose more heat by radiation,
and it is for this reason that the food for the growing child must be
wisely and carefully selected.

DIET FOR CHILD TWO