CHAPTER VI.

Fats and Oils.


Fats and oils contain three elements--carbon, oxygen and hydrogen.
About one-fifth of the body is composed of fat. Before death results
from starvation 90 per cent. of the body fat is consumed.

USES OF FAT.

(1) To furnish energy for the development of heat; (2) to supply
force; (3) to serve as covering and protection in the body; (4) to
lubricate the various structures of the body; and (5) to spare the
tissues. The fats and oils used as food all serve the same purpose,
and come before the carbohydrates in fuel and force value; in
combination with proteids, they form valuable foods for those engaged
in severe muscular exercise, such as army marching, mining
expeditions, etc.

Fats and oils are but little changed during digestion. The fat is
divided into little globules by the action of the pancreatic juice and
other digestive elements, and is absorbed by the system. Fat forms the
chief material in adipose tissue, a fatty layer lying beneath the
skin, which keeps the warmth in the body, and is re-absorbed into the
blood, keeping up heat and activity, and preserving other tissues
during abstinence from food. Fat sometimes aids the digestion of
starchy foods by preventing them from forming lumpy masses in the