This table represents the fuel value and comparative amount of actual nutrients in the foods mentioned.

POTENTIAL ENERGY OF FOOD.

The Five Food Principles

The five food principles are water, proteids, fats, carbohydrates and salts or mineral matter.

Water is the medium which floats things through the body.

The Proteids, called also albumenoids, are flesh foods which build and restore the body. They are called nitrogenous foods.

The Fats give off heat and serve indirectly as a source of muscular energy, and are called carbonaceous foods.

The Carbohydrates, sometimes called work foods, furnish fat to tissues and are the main source of muscular energy.

The Salts combine with fluids and solids of foods and aid in forming bone, and also aid in the process of digestion.

Water is the most abundant natural product. In the human body fully 70 per cent, of its weight is water, and all the tissues and secretions and the hair, nails and teeth contain a small amount.

In a human body weighing 150 pounds the average weight of the component parts is as follows:

Pounds.

Ounces.

Water..........................

105

....

Albumen and similar substances......

17

4

Fat..............................

5

...

Bone.............

4

6

Cartilage...........

1

6

Mineral matter.....

13

• •

Keratin (hair, nails and a mixture of nitrogenous substances).....

4

Total......................

150

The quantity of food required to keep the body in good working condition depends upon the temperature, the season and climate, work, exercise and occupation, age, sex and clothing.

Uses Of Food In The Body

Food supplies the wants of the body in several ways. It either -

1. Is used to form the tissues and fluids of the body.

2. Is used to repair the wastes of the tissue.

3. Is stored in the body for future consumption.

4. Is consumed as fuel, its potential energy being transformed into heat or muscular energy or other forms of energy required by the body; or

5. In being consumed protects tissue or other food from consumption.

Ellen H. Richards makes the foregoing statements and after several interesting tables goes on to give us: