In order to understand the relation of food to the sustenance and
repairing of the body, it will be necessary to learn, first, of what
the body is composed, and the corresponding elements contained in the
food required to build and keep the body in a healthy condition. The
following table gives the approximate analysis of a man weighing 148
pounds:--

Oxygen 92.1 pounds.
Hydrogen 14.6 "
Carbon 31.6 "
Nitrogen 4.6 "
Phosphorus 1.4 "
Calcium 2.8 "
Sulphur 0.24 "
Chlorine 0.12 "
Sodium 0.12 "
Iron 0.02 "
Potassium 0.34 "
Magnesium 0.04 "
Silica ? "
Fluorine 0.02 "
------
Total 148.00 pounds.

As food contains all these elements, and as there is constant wearing
and repair going on in the body, it will be readily seen how necessary
some knowledge of the relation of food to the body is, in order to
preserve health.