PROTEINS
12% OF A BALANCED DIET
ROLE
The primary role of proteins is to serve as the structural unit
to build and repair body tissues, including muscle and
connective tissue.
VS.
The primary role of a carbohydrate is to provide energy to the
body (especially the brain).
SECONDARY ROLE
Proteins also help regulate body metabolism and provide
protection from disease by helping create:
Helping Agents Such as:
• Enzymes
• Hormones
• Antibodies
Metabolism is a collection of
chemical reactions that
constantly takes place in the
body's cells. Metabolism
converts the fuel in the food
we eat into the energy
needed to power everything
we do, from moving to
thinking to growing.
NOT ALL PROTEINS
ARE CREATED EQUAL
First, proteins are made up of Amino Acids.
Think of a protein as a necklace. Each bead is an amino acid.
There are 22 different amino acids, and they combine in
different ways to make different proteins (each protein has
it’s own job).
-
Essential Amino Acids – the body needs to get them from
food – 9 out of the 22.
-
Nonessential Amino Acids – the body can make the on it’s
own – 13 out of the 22.
PROTEINS IN FOOD
 Complete Proteins: contain all of the essential amino
acids
 found ONLY in Animal foods and soy products
 Incomplete Proteins: missing one or more of the essential
amino acids.
 present mostly in vegetable sources
 Vegetarians who avoid animal foods must be careful to eat
a mixture of different foods so that they get all the
essential amino acids.
PROTEIN FOR
GROWTH
Because of its role in building body tissue, protein is very
important during stages of rapid growth – such as
adolescence.
Adolescents need to take in more that 12% of their calories
from protein.
For adolescents, the recommended dietary allowance (RDA)
for proteins is 1 gram per kilogram of body weight.
Calculating your Protein
Needs
• 1. Determine your body weight
• 2. Convert pounds (lb) to kilograms
(kg) by dividing number of pounds
by 2.2
• 3. Multiply by 0.8 (adult females) or
0.9 (adult males) to get an RDA in
grams per day.
Example
1. An adult female weighs
132 lbs
2. 132/2.2 = 60 kg
3. 60 kg x 0.8 = 48 grams a
day
IMPORTANT NOTE
Because the average person in first world countries consume
more than enough protein, the nutritional problem related to
protein intake is more in terms of too much, or excess.
Protein foods from animal sources are often high in fat (and
high in calories), which can lead to increased risk of heart
disease, cancer and obesity.