Transcript Sports Nutrition - Columbia Public Schools

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Targeted nutritional split:
 50-55% carbohydrates
 20-25% fats
 25% proteins
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Caloric needs of an athlete depends on
intensity, frequency and duration of exercise
 Compared to sedentary individuals, athletes need
~25% more calories
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Supplements not necessary if diet is
adequate
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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
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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
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Four Goals:
 Prevent low blood sugar
 Settle your stomach
 Fuel your muscles
 Pacify your mind that your body is well fueled
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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
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Familiar foods
Drink plenty of fluids
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Eat 100-300 calories of carbs per hour of
exercise
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High glycemic index foods
 Glucose enters bloodstream quickly
 Sports drinks, Sports bars, Potatoes, Corn flakes,
Honey
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Priority #1 = re-hydrate!
Replace glycogen
 Consume ~300 calories of moderate-to-high
glycemic foods within 15 minutes
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Some protein enhances glycogen replacement
& muscle repair
 Eat 1 gram of protein per 3 grams of carbohydrate
▪ Example: slice of turkey with a bagel
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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
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Myth: Athletes should eat a low-carb diet.
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Truth: Carbohydrates are the limiting factor
for endurance athletes… you must have
enough stored!
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Simple or complex doesn’t matter. Glycemic
response does.
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Myth: I should eat lots of carbs before my
endurance events.
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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
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Definition:
 Relative amount of fat, muscle, bone and organs
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Two Component Model
 Lean Body Mass: skeletal muscle, bone, water
 Fat Mass: storage fat (subcutaneous, energy reserve &
cushioning) & essential fat (necessary for physiological
functions)
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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
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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)
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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”?
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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
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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
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DEXA (Dual Energy X-Ray Absorptiometry)
 Method: Two x-ray energies are used to measure body fat,
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muscle & bone mineral
Can provide whole body estimates of body fat as well as
regional body estimates
Fast to perform
Expensive
“Gold Standard”?
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Potentially fatal medical condition driven by sports
that demand unrealistic body shapes and/or
weights
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Who is at risk?
 Participants of dance, gymnastics, figure skating, ballet,
cross country
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Prevention?
 Increase caloric & calcium intake
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Three components:
 Disordered eating
 Amenorrhea
 Osteoporosis
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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
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Who is at risk?
 Occurs mostly in men
 Predominant in sports that focus on body size & form (i.e.
bodybuilding)
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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
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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
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Concerns?
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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