Essentials of Nutrition for Sports

Most vegetables and fruits consumed as such contain only small

amounts of fat. Saturated Fats

Often solid at room temperature, saturated fats are high in well-

marbled meats and whole-

milk dairy products.

High amounts of saturated fat are found in beef, pork, lamb,

chicken skin, butter, whole milk, and cheese.

Some vegetable fats are also saturated; for example, palm kernel

and coconut oils. Polyunsaturated Fats

Vegetable oils are the principal sources of linoleic and alpha-

linolenic acids. Arachidonic acid is found in small amounts in lard, which also contains about 10% of linoleic acid. Fish oils contain large quantities of a variety of longer chain fatty acids having three or more double bonds including eicosapentaenoic and docosahexaenoic acids. Trans (Hydrogenated) Fats

A small amount of

trans

fat is found naturally in animal-based

foods. Most

trans

fat is a specific type of fat formed when liquid oils

are made into solid fats like s

hortening and hard margarine.

Food manufacturers solidify unsaturated liquid fats through a

process called hydrogenation. This is used to create margarine or shortening for use in deep-fat frying or as an ingredient in baked goods, snack foods, crackers, and candy. Hydrogenation increases the shelf life and flavor stability

of foods containing these fats.

The FDA estimates the average adult US daily intake of

trans

fat

is 5.8 grams or 2.6% of calories.

On average, Americans consume 4 to 5 times as much saturated

fat as

trans

fat in their diet.

Heart-Healthy Fat

For more information about saturated, unsaturated, and

trans

fats, see

Heart-Healthy Fat

on page

87

.

Function, General

Dietary fat is a major source of energy. Fat provides about two-

thirds of the energy muscles require. It provides the most concentrated source of energy of any foodstuff, 9 calories per gram.

Fat is required for the absorption of fat-soluble vitamins

(vitamins A, D, E, and K) and carotenoids.

As a food ingredient, fat provides taste, consistency, and stability

and helps us feel full.

Fat is important for proper

growth, development, and

maintenance of good health.

Fat maintains healthy skin and ha

ir, cushions the bones and vital

organs, and protects the body from cold temperature. Energy

More than 80% of alpha-linolenic acid and much linoleic acid

are consumed in energy production.

Essential Fatty Acids

By definition, essential fatty acids cannot be synthesized in the

body and are required for health.

The main biological roles of essential fatty acids are as

regulators of gene expression; as structural components of cell membranes, particularly in nerve tissue and in the retina; and as precursors of eicosanoids. Linoleic Acid

Linoleic acid is essential as a precursor of arachidonic acid, a

substance required for the production of eicosanoids. Read more about eicosanoids on the next page.

Nutrition for Sports, Essentials of 79