Transcript Nutritional Recommendations for the Physically Active Person

Nutritional
Recommendations for the
Physically Active Person
Chapter 7 Part 1
The Optimal Diet
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Supplies required nutrients in adequate
amounts for:
 Tissue maintenance and repair
 Growth without excess energy intake
The Optimal Diet
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Proper nutrition helps:
• Improve athletic performance
• Optimize programs of physical conditioning
• Improve recovery from fatigue
• Avoid injury
Energy Balance Equation
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Body mass remains constant
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3500 kCal approximately equals 1 lb of
stored body fat.
 Caloric intake equals caloric expenditure.
 Consume 3500 extra kCal, gain 1 pound
 Expend 3500 kCal, lose 1 pound
Energy Balance
Principles of Good Eating
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Variety
• Creates a diet with sufficient amounts of
required nutrients.

Balance
• Intake of nutrients from the major food
groups.
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Moderation
• Planning to maintain a balanced nutrient
intake throughout the day.
My Pyramid
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www.mypyramid.gov
Can be personalized
 Based on age, sex, and level of daily exercise
Figure is to emphasize at least 30
minutes of moderate to vigorous daily
physical activity
Based on the 2005 Dietary Guidelines
for Americans
My Pyramid
Dietary Guidelines for
Americans
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Control caloric intake to manage body
weight.
Consume a variety of foods.
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Increase daily intake of:
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• Within the basic food groups
 Fruits, vegetables, whole grains, and nonfat
or low-fat milk and milk products.
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Choose fats wisely for good health.
• Limit saturated fats and trans fats.
Dietary Guidelines for
Americans (cont.)
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Choose carbohydrates wisely for good
health.
Choose and prepare foods with little salt.
If you drink alcoholic beverages, do so in
moderation.
Be physically active every day.
Keep food safe to eat.
Serving Size Versus Portions
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The USDA defines a standard serving of
pasta as one-half cup.
The FDA, which regulates food labels,
claims a standard serving is 1 cup.
Typical restaurant pasta portion averages
about 3 cups.
• Equal to 6 servings according to MyPyramid
Mediterranean and
Vegetarian Diet Pyramids
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Mediterranean
• Emphasizes fruits, nuts, vegetables, legumes,
•
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all manner of unrefined grains, and protein
derived from fish, beans, and chicken
High monounsaturated fatty acid content
Vegetarian
• Consists of foods from the plant kingdom
Protein Intake - Physically Active
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RDA = 0.8 g/kg of body mass
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Eating a high-carbohydrate diet
 Is it enough?
 Adequate to conserve muscle protein during
intense training.
Protein Intake - Physically Active
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Those in endurance training
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Those who resistance train
 1.2 to 1.6 g/kg/day of high-quality protein
 1.0-1.6 g/kg of body mass.
Protein Metabolism
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Enter (AA pool)
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Dietary
Tissue breakdown
Nonessential – formed in body
Protein Metabolism
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Exit - (AA pool)
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Into gut
Into tissue structure
AA N2 lost in urine, sweat
Oxidized
Stored as CHO, fat
Protein Synthesis
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Protein synthesis
• Gene expression
• Each gene directs synthesis of one protein
• DNA is transribed to mRNA (messenger RNA)
• mRNA takes the message out to the ribosome
• tRNA (transfer RNA) is also required to make
the new molecule
Protein Needs-Physical Exercise
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Rodent muscle
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Increased degradation of muscle protein
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Significant muscle damage
• 113% increase in muscle urea N2 content
• 1 h running
• Kasperek & Snider, 1989
• Armstrong et al. 1983
• Significant eccentric component
Protein Needs-Physical Exercise
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Research questions
• Does increased protein intake reduce this
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damage?
Does increased protein intake speed the
repair processes?
Protein Needs-Physical Exercise
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Branched chain amino acids (BCAA)
• Predominantly oxidized during endurance
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exercise
Related to availability of BCAA and inversely
proportional to glycogen availability
• Increased BCAA/glycogen at end of prolonged run
• Fasting state
Branched Chain Amino Acids
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Daily requirements
• Single bout of exercise
• 2 h 55% VO2max
• Oxidation rate equivalent to 90% daily
requirement
Endurance Exercise and Protein Metabolism
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Energy requirement – 1 h 65-75%VO2max
kcal/h
%fat %pro %CHO
Males 838
23
5
72
Protein Synthesis
High Protein Intake
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Concerns?
• Kidney failure
• Rodents – 80% protein
• No problems
• Absence of reports of kidney problems in weight
lifter/body builders
• High protein diets 20-30 years
• Excess N2 not a problem – In healthy individuals
High Protein Intake
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Concerns?
• Dehydration
• Excess water loss with nitrogen excretion
• Sweat loss
• Proper rehydration – monitor body weight