Essentials of Nutrition for Sports

Fats: Types, Structure

This section is somewhat technical. If you do not have a

scientific bent, you may prefer to skip on to

Dietary Fat

on page

77

.

Fats or Lipids

The term lipids includes many compounds: triglycerides, mono-

and diglycerides, phosphatides, cerebrosides, sterols, terpenes, fatty alcohols, fatty acids, fat-soluble vitamins, and other substances.

Triglycerides

At normal room temperatures, triglycerides range in consistency

from solids to liquids. When solid th

ey are referred to as “fats” and

when liquid they are called “oils.”

Fatty acids are rarely found unattached in the body.

Figure 12. Triglyceride structure. Three fatty acids attached to a RED glycerol backbone. The RED circle outlines a

cis

-unsaturated double

bond. Cis- and trans-double bonds are discussed on page

76

.

Most of the fats we eat are triglycerides—three fatty acids
attached to a glycerol molecule.

The glycerol holds the three fatty acids. It is a relatively small

part of the fat molecule. One hundred grams of fat or oil will yield about 95 grams of fatty acids and 5 grams of glycerol.

The physical and chemical characteristics of fats are influenced

by the kinds and proportions of the component fatty acids and the way in which these are positioned on the glycerol molecule.

Fatty Acids

Fatty acids are linear hydrocarbon chains containing from 4 to 30

hydrocarbons, most commonly 12 to 24 carbons.

One end of the molecule contains a carboxylic acid group from

which chemists count the number of carbons. The other end is the methyl, “n,” or omega end from which nutritionists and biochemists count the position of the first double bond in unsaturated fats.

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Methyl group

Long hydrocarbon chain

Carboxyl acid

group

Figure 13. Chemical features of a fatty acid. This is the saturated palmitic acid.

Saturated Fats

An octopus has eight arms. Think of a tetrapus carbon as having

four arms. In fats, these four arms hold on to other carbons, hydrogen, or oxygen.

Nutrition for Sports, Essentials of 74