Exercise and Proteins
Amino
Acids
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Definition: the building blocks of
protein
Contain a + charged
amine group (NH2) and a charged organic group (COOH)
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20 different amino acids are required
by the body:
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8 (9 in infants) essential- must get
from diet
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12 non-essential- body manufactures
itself
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Other definitions:
Complete proteins
contained in foods that contain all of essential a.a.
Incomplete
proteins contained in foods that lack one or more essential a.a.
Sources
of Protein
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2/3 of dietary protein in American diet comes from
animal sources
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These contribute high level of complete proteins
Eg. Eggs, milk, meat, fish & poultry
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Other 1/3 of dietary protein comes from plant sources
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Greater percentage of incomplete proteins so must eat
a greater combination
Proteins
Role in Body
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12-15% of body mass is protein
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65% of the body protein mass is
skeletal muscle
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Building blocks for RNA & DNA
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Form the heme portion for hemoglobin
and myoglobin
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Form hormones and neurotransmitters
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Activate vitamins
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Important for structural growth (e.g.
plasma membranes and internal cell structures)
Recommended
Protein Intake
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0.83 grams per kilogram of body wt.
for average individual
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Pregnant women should increase daily
protein intake by 20 g/day
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Nursing females should increase daily
protein intake by 10 g/day
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Athletes should maintain the 0.83
g/kg amount
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Heavy training of 2-6 hr/day may
consume 1.2-1.8 g/day if diet is incomplete
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High level of CHO should be
maintained in diet to prevent dependence on protein for energy
How Protein is Converted to CHO
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Alanine-Glucose Cycle*
Alanine released from highly active muscle
Delivered to Liver
Converted to
Glucose
Transported
Back to Active Muscle
* May contribute up to 10-15% of total energy requirement
from long-term, high-intensity exercise
Dietary
Calories
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Calorie= quantity of heat required to
raise temp of 1 kg of water by 1oC
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Determined through use of bomb
calorimeter; however, based on digestive efficiency
1 g of CHO yields 4 kcal/gram
1 g of Fat yields 9 kcal/gram
1 g of Protein yields 4 kcal/gram
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Ultimately
A Calorie = A Calorie
(regardless of food source; eg. 1 tablespoon of mayonnaise and 20 celery
stalks are both ~ 100 kcals