Sports Nutrition - Columbia Public Schools
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Transcript Sports Nutrition - Columbia Public Schools
Targeted nutritional split:
50-55% carbohydrates
20-25% fats
25% proteins
Caloric needs of an athlete depends on
intensity, frequency and duration of exercise
Compared to sedentary individuals, athletes need
~25% more calories
Supplements not necessary if diet is
adequate
Glycemic response:
Food’s ability to contribute glucose to the
bloodstream [page 110 Nancy Clark]
Influenced by:
▪ Amount eaten
▪ Fiber content
▪ Amount of added fat
▪ Preparation of food
Drink EARLY
Prior to exercise– the need for water increases during physical
activity
Drink OFTEN
During exercise- combat fluid loss from sweat and respiration
Drink AFTER
Aids in cooling the body post-exercise
Sport drinks:
Contain carbohydrates (energy) and electrolytes (sodium)
Recommended for exercise lasting longer than 1 hour
Four Goals:
Prevent low blood sugar
Settle your stomach
Fuel your muscles
Pacify your mind that your body is well fueled
High in carbohydrates, Low in Fat
Carbs move quickly through digestive system
Brain does not store glucose & can’t burn fat so
maximal brain fx comes if you eat close to your
event
Low-to-moderate glycemic index foods; glucose
enters bloodstream slowly so sustains energy
▪ Rice, pasta, bananas, yogurt, oatmeal, apples
Familiar foods
Drink plenty of fluids
Eat 100-300 calories of carbs per hour of
exercise
High glycemic index foods
Glucose enters bloodstream quickly
Sports drinks, Sports bars, Potatoes, Corn flakes,
Honey
Priority #1 = re-hydrate!
Replace glycogen
Consume ~300 calories of moderate-to-high
glycemic foods within 15 minutes
Some protein enhances glycogen replacement
& muscle repair
Eat 1 gram of protein per 3 grams of carbohydrate
▪ Example: slice of turkey with a bagel
Don’t forget the power of… REST!
Quality training is better than quantity training
Myth: Athletes should eat as much protein as
possible.
Truth: Max. usable amount = 1 g/lb of body wt.
Too much protein can be a hindrance to
performance
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Feel full before you get adequate carbohydrates
Proteins tend to also be high in fat… weight gain!
Overburdens the kidneys
Risk of dehydration increases
Loss of calcium from bones
Only 1/3 of dinner plate should be protein foods
Myth: Athletes should eat a low-carb diet.
Truth: Carbohydrates are the limiting factor
for endurance athletes… you must have
enough stored!
Simple or complex doesn’t matter. Glycemic
response does.
Myth: I should eat lots of carbs before my
endurance events.
Truth: Change your training, not your diet!
7-10 days prior to event, taper training
Maintain normal diet & carb intake
The calories you normally burn in extra training
will be stored as glycogen
▪ Result = double your glycogen stores
Definition:
Relative amount of fat, muscle, bone and organs
Two Component Model
Lean Body Mass: skeletal muscle, bone, water
Fat Mass: storage fat (subcutaneous, energy reserve &
cushioning) & essential fat (necessary for physiological
functions)
Body Mass Index
Rationale: healthy ranges of body weight exist for
individuals of varying heights
Method: mathematical calculation
▪ BMI = weight (kg)/height (m2)
Accessible, inexpensive, acceptable for average
population
Not useful for children, teens, pregnant women
Not useful for athletes
▪ Does not account for weight of muscle mass
Skinfold Calipers
Rationale: total body fat can be estimated from
subcutaneous fat levels
Method: Measure at multiple sites and calculate using
formulas to arrive at predicted % body fat
Inexpensive
Accuracy: +/- 4%
(when performed by an
experienced individual)
Hydrostatic Weighing (Underwater
Weighing)
Rationale: Those with high % of lean
body mass weigh more in water than
those with high % of fat mass
Method: Water displacement
▪ requires measurements of body density on
land, underwater weight, water density at
testing temp, residual lung volume
▪ Can be difficult to perform accurately
“Gold Standard”?
Bod Pod
Rationale: Similar to Underwater Weighing
Method: Air Displacement as opposed to water
Accuracy +/- 2%
Expensive but easy to use
Cannot move during
assessment
May accommodate
heavier/larger individuals
Bioelectrical Impedance
Rationale: Electricity is not conducted as well
through fat mass as it is through lean body mass
Accuracy: +/- 3%
Easy to use; cost varies according to
quality of tool
Tends to overestimate lean people
and underestimate obese people
Hydration can effect results
DEXA (Dual Energy X-Ray Absorptiometry)
Method: Two x-ray energies are used to measure body fat,
muscle & bone mineral
Can provide whole body estimates of body fat as well as
regional body estimates
Fast to perform
Expensive
“Gold Standard”?
Potentially fatal medical condition driven by sports
that demand unrealistic body shapes and/or
weights
Who is at risk?
Participants of dance, gymnastics, figure skating, ballet,
cross country
Prevention?
Increase caloric & calcium intake
Three components:
Disordered eating
Amenorrhea
Osteoporosis
Overwhelming compulsion to acquire more lean body
mass
Perceive themselves as having small musculature despite
high levels of muscle development
Associated with anxiety and depression
Precipitates disordered eating (excess protein is common)
Many turn to steroids & supplements
Who is at risk?
Occurs mostly in men
Predominant in sports that focus on body size & form (i.e.
bodybuilding)
Dietary supplement
A product intended to “fill in the gaps” in the diet;
must contain at least one dietary ingredient
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Vitamins
Minerals
Herbs
Amino acids
Enzymes
Not regulated by the FDA
Not subject to pre-market safety evaluations
Labeling cannot claim to diagnose, prevent,
treat or cure a disease
Manufacturer is responsible for safety
Not required to report injuries or illnesses related
to their product to the FDA
Concerns?
Ergogenic Aid
Any substance taken to enhance athletic
performance
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Mechanical
Nutritional (includes dietary supplements)
Pharmacological
Physiological
Psychological
May or may not be legal