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SPORTS NUTRITION
LESSON 29
Dietary Protein
WHAT IS PROTEIN
Protein is a complex chemical structure containing carbon, hydrogen and oxygen.
In this way it is the same as carbohydrate and fats.
It is different because protein has one other essential element - nitrogen.
About 16% of protein is nitrogen.
Dietary Protein
Carbon, Hydrogen, Oxygen and Nitrogen combine in different structures.
The different element combinations are called amino acids.
There are 20 different amino acids, all of which can be combined a variety of ways
to form the proteins necessary for the structure and function of the body.
The body may also modify the structure of amino acids converting them into the
amino acid needed.
Dietary Protein
Proteins are created when 2 amino acids link and form a peptide bond, or a
dipeptide.
Most proteins are polypeptides containing up to
300 amino acids.
Protein is contained in both plant and
animal foods.
Dietary Protein
IS THERE A DIFFERENCE BETWEEN PLANT AND ANIMAL PROTEIN?
Humans can synthesize some amino acids in their bodies.
There are 9 amino acids that humans cannot synthesize. They are called
essential amino acids.
For optimal maintenance, growth and development, all 20 amino acids must be
present at the same time.
Dietary Protein
Dietary sources of protein vary widely in their composition and nutritional value.
The quality of a protein source depends on its ability to provide the nitrogen and
amino acid requirements for maintenance, growth, repair, and development.
Key Factors:
Digestibility
Ability to provide the essential amino acids
Dietary Protein
The National Academy of Sciences has created a method of scoring proteins.
They are assessed and given a number value.
Those proteins that contain an adequate content of all 9 essential amino acids are
given a high score and are called complete proteins.
Those that are missing one or more of the essential amino acids and are unable to
adequately support life or growth are called incomplete proteins, or low quality
proteins.
Dietary Protein
Protein from animal sources is general considered to be of a higher quality that
protein from plant sources.
That does not mean plant amino acids are inferior amino acids, they are the same.
The difference is in the distribution.
Animal protein is a complete protein because it contains each essential amino
acid in the correct proportion to human requirements. All 20 amino acids are
present simultaneously.
Dietary Protein
Plant proteins can provide you with all the protein to support growth and
development. However proteins usually exist in smaller contractions, and not all 9
essential amino acids are present.
People eating only plant food must be careful to choose plant foods that will
supply all 9 of the essential amino acids.
This is commonly known as protein complementing.
Dietary Protein
WHAT ARE SOME COMMON FOODS THAT ARE GOOD SOURCES OF
PROTEIN?
Animal Foods - All foods in the meat, milk and egg groups generally have
substantial amounts of high-quality protein.
Dietary Protein
Plant Foods
Legumes - relatively good sources of protein
Black beans, garbanzo beans, lima, navy, pinto, etc.
Nuts
Relatively high in protein, but high in fat
Fruits and Vegetables
Contain some protein in varying amounts
Dietary Protein
HOW MUCH DIETARY PROTEIN DO I NEED?
Humans do not actually need protein, they need amino acids and nitrogen. These
amino acids and nitrogen are supplied in protein foods.
There are a variety of ways of measuring how much protein we need. We will
discuss the RDA.
Dietary Protein
RDA of Protein
The recommended amount of protein varies with a number of factors.
Stage of the life cycle
Young
Old
Etc.
Size
Dietary Protein
CALCULATE YOUR PROTEIN NEEDS
0.36 g protein/pound of body weight x pounds =________g protein/day
Each gram of protein has 4 calorie.
Calculate the number of calories provided by protein._________
Based on your calorie intake level, what % of your calories are you getting from
protein.___________
How does this compare with the recommendations?
Dietary Protein
HOW CAN I BE SURE I GET ENOUGH OF EACH OF THE ESSENTIAL AMINO
ACIDS?
Well, you can count the amount in grams in each food you consume, add them up
and compare them with a chart of how much you need of each.
Or - you can eat a wide variety of animal and plant foods - High-quality, nutrient
dense, low fat foods.
Other than being a risk factor for CHD, why is it important to consume lower fat
foods?
Dietary Protein
Go to www.ChooseMyPlate.gov
Click on Food Groups
Choose Protein Food Groups
List what foods are the healthiest choices.
Go to the Food Gallery and explain or illustrate what a serving size is for each of
the healthiest choices.
From the home page find “10 tips Nutrition Education Series”. Explain what you
learn.