Sports Nutrition for the Adolescent Athlete

advertisement
Performance
Nutrition
Carrie Peterson MS, RD, LD, CSSD
[email protected]
Brief History of Sports Nutrition

Documentation of “special”
foods and nutrition strategies
dating WAY back….
 Greek Olympians in
300BC used specific
mushrooms to enhance
performance
 In 1800’s Dutch
swimmers used caffeine
before races, Belgian
swimmers dipped sugar
cubes in ether before
racing.
Brief History of Sports Nutrition



Evolution of Gatorade in 1960’s by 4
physicians at the University of Florida
to help the football team. Initially met
with skepticism that taking in sugar and
salt could be beneficial… it caught on
fast!
Late 1980’s; some colleges, university
and professional teams began hiring
and consulting with RD
Well-known athletes started crediting
nutrition with their success.
Brief History of Sports Nutrition

Lab-Based Sports Nutrition research started in
1960’s at Ball State University under direction of
Dr. David Costill

Effects of nutrition on performance, muscle
biopsies, gastric emptying studies….
Completing the Puzzle
Training
Rest/Recovery
Supplementation
Treatment
Diet/Nutrition
What Influences
Athletic Ability?
Genetic Endowment
Optimal Training
Good Nutrition
No “secret” ingredient!
Performance Nutrition Means…



Fueling to boost activity performance on a daily basis
Fueling to decrease the risk of injuries, recover fully
after workouts and stay healthy
Fueling with foods that taste good, foods you enjoy,
foods that can be prepared easily, and foods you feel
confident eating
Consequences of Poor Nutrition









Weight loss
Strength loss
Lethargy
Chronic Fatigue
Soreness, joint pain
Micronutrient Deficit
Respiratory Infections
Diminished Performance
“Overtraining Syndrome”
Physical Activity Factor Varies Widely
Examples

Female Olympic Gymnasts


Tour de France Cyclists


1900 kcal/day
7,000+ kcal/day
College Football Players (in wt gain mode)

7,500-8,500 kcal/day
Marvin Austin
6’3”, 312 pounds
21 years old
4.69 40 yd dash
Jordan Hasay
5’1”, 98 pounds
19 years old
4:42.21 mile
Energy Needs
Basic Calorie Requirement
15-30 kcal/#
Calorie Needs for Athletes
Calories expended =
RMR + TEF + PA
Calories
Consumed
Calories
Expended
Rule of Thumb:
Walk or run 1 mile = 100 kcals burned
Energy Needs
Calories/#
120#
LOW - sedentary
1560- 1800
ACTVE (30-60min)
1920-2160
160#
240#
2080-2400
3120-3600
2560-1880
3840-4320
MODERATE (1-1.5hr)
2280-2520
3040-3360
4560-5040
HIGH (1.5-2hr)
2640-2880
3520-3840
5280-5760
4000-4800
6000-7200
VERY HIGH (2-3hr)
3000-3600
Carbohydrates (CHO)
Fuel Muscle

A muscle is like a sponge

Keep muscles full of fuel
Carbohydrates reach muscles quickly
Substrate used to form Glycogen
Glycogen is the PRIMARY energy source



The Effect of Diet on Physical Endurance
Maximum
endurance time:
Fat and protein diet
57 min
Normal mixed diet
114 min
High-carbohydrate diet
167 min
Carbohydrate
THE CHALLENGE?
Maintain CHO supply to muscles and slow it’s depletion
by using fat as fuel
Carbohydrates = FUEL

Carbohydrate Needs:





30 minutes moderate exercise: 4-6 gm/kg (1.8-2.7 gm/#)
1 hour intense training/day: 7gm/kg (3gm/#)
1-2 hours intense training/day: 8-9 gm/kg (3.5-4gm/#)
2-4 hours intense training/day 9-10gm/kg (4-4.5 gm/#)
Ultra endurance athlete: >12gm/kg (5.5gm/#)
150-lb student who does
Aerobics classes:
165 Pound Soccer Player:
675 gm/day
300 gm/day
Sample Athlete




Male soccer player
Training 2-3 hours/day
165 lbs = 75kg
9gm CHO/kg =
675 gm CHO
What does 675gm of CHO
mean to an athlete?
2 large bagels
2 cups cereal
2 slices bread
2 cups milk
1 cup fruit yogurt
2 cups pasta/sauce
1 cup beans
2 pc fruit
1 cup fruit juice
2 starchy veggies
4 cups Sport Drink
20oz Soda
70g
90g
30g
25g
45g
100g
45g
50g
30g
60g
60g
70g
675g
Protein
Role in Exercise?




Muscle growth and repair
Supplies 10% of fuel when glycogen stores are low
Supplies 5% of fuel when glycogen stores are high
Aids in repair/recovery following muscle damage
Individuals with Higher Protein
Needs


New training program
Energy Restriction





Diet or extreme expenditure
Vegetarians
Disease
Injury rehab
Young or old athletes
These aren’t the
people typically
using protein
supplements!
Protein for Tissue and Muscle
Building and Repair
Protein Needs: 1.2 to 1.7 g/kg (0.5 – 0.8g/#)





Some research supports up to 2 gm/day
Protein intake and timing of protein intake are both important for
increasing lean muscle mass
Eating protein several times a day may enhance availability of amino
acids during workout
Going into strength workouts well nourished may enhance strength
gains and decrease protein losses
Refueling immediately after workouts with a carbohydrate/protein
mix is essential for strength gains
Vegetarian Athletes

Vegetarian athletes (like others) must learn to
complement proteins

Vitamin B12, calcium, iron, and zinc

Eating enough calories can be difficult

Vegetarian diets are
in bulk &
in calories
Nutrition MISTAKE
Thinking that….

All vegetarian athletes are healthy eaters
Some vegetarian athletes suffer less heart disease,
cancers, high BP, and DM – but studies show it is
more likely to be from a generally healthier lifestyle
 Vegetarian diets can be unhealthy if meat and other
animal products are not substituted by nutritionally
appropriate foods
 Vegetarian athletes need to pay particular attention
to iron intake because iron from plant sources is
more difficult for the body to absorb!

2,500 kcal Vegetarian Meal Plan


Breakfast:
 1 cup iron-fortified cereal
(5mg)
 1 cup skim milk or soy
milk
 12oz Orange Juice
(vitamin C)
Lunch:
 Spinach Salad w ¼ c
sunflower seeds & Drg
(7mg)
 Veggie Burger w cheese
on bun (3mg)
 1 fruit yogurt (vit C)


Snack
 2 oatmeal raisin cookies
(3mg)
Dinner
 Tofu/Broccoli stir fry or 2
slices cheese pizza (6mg)
 1 cup rice (1mg)
 1 cup ice cream
Vitamins & Minerals
Which Are Most Important?


Thiamin, riboflavin, niacin
Sodium & electrolytes



Antioxidants – A,C,E
Blood-building nutrients
(folic acid, B12, iron)
Calcium
Nutrition MISTAKE
Thinking that….
 Vitamins and minerals give athletes extra energy they
need to compete



Act as co-factors to unlock the chemical energy stored in
food
Meals rich in grains, vegetables, fruit, meat and dairy give
athletes energy
Multi vitamin/mineral supplement may be necessary for
some as an “insurance policy”
Iron & Calcium
Both:
Increased small losses in athletes in sweat & urine.
Calcium:

Increased risk of stress fractures
(stress fractures account for 15% of all running injuries*)

Decreased bone-mineral content & density
Most girls age 12-19 consume ~790mg/day
50% of adult women consume < 700mg
*(Exercise Sport Science Review, 2006)
Popular Vitamins for Athletes
“Mega Men”
 20 vitamins & Minerals listed
 11 in amounts > 100% US RDA
 3 in amounts > 1000% US RDA
 18 other substances
Some interact with corticosteroids,
anti-coagulants, & antiplatelet agents
Vitamins for Athletes


Look for no more than 100%
USRDA of any one vitamin
or mineral
Take only one each day
Hydration
Components of Muscle
20%
Protein
75% Water
5% other
Fluids & Hydration
Males - 60% body wt.
Females - 50% body wt.





Cardiovascular function
Thermoregulation
Injury prevention
Performance
Recovery
Sweat losses during 2 hours of exercise
can = 2 liters or more
Physiological Effects of
Dehydration



sweat rate
blood volume &
heart rate
core body heat
cardiovascular function
-less O2 and nutrient-rich blood to muscles
-more reliance on anaerobic system

Slower removal of wastes
cramping, fatigue
Impaired Performance!

Muscle strength
Speed
Stamina
Energy
Cognitive Process

Risk of Injury




95% of muscle cramps are due to dehydration!
Sweat Loss and Fatigue
Sweat loss in athletes 1-12 quarts/day!
Sweat Rate Equation:
2 hour workout…..
Pre weight 180.0#
Post weight 178#
Fluid Intake: 32oz of water and sports drink
140-138=32 ounces of fluid lost + 32 ounces consumed = 64 ounces of
sweat loss per 2 hours or 32 ounces loss per hour!
This is an example to drink at least 8 ounces of fluid every 15 minutes
or double current intake
When Should You Drink?
WHEN TO DRINK
AMOUNT OF FLUID
2 hr before exercise
2-3+ cups
15 minutes before
1-2+ cups
Every 15 minutes DURING
1-1.5 cups
After Activity
2-3 cups
for every lb lost
*ACSM Position Paper, 2006
What you already know…

Don’t rely on thirst


Already 1-2% dehydrated
Drink before, during & after
2 hrs before 14-24 oz
 20-36 oz/hr or 5-12 oz every 15 mins.
 drink ~150% or 24oz / # lost


Water is fine for <1 hr; sport drinks > 1 hr
4-8% carb, 0.5-0.7 g Na+/L
 pop, fruit juices or fruit drinks >10% may  emptying

Dehydration
Planned rehydration is necessary
 typically only 1/3 to 2/3 of the volume lost is replaced
voluntarily


Hockey player ave. loss of 3-5%
1 # weight loss = 16 oz. of fluid
 160 # player loses 5%  ~ 8 #
8 #  requires 128 oz of fluid to equal loss
 ~6  20 oz sport bottles = 128oz [3.8L]
 actually recommend 150% 
 ~ 10
20oz-sport bottles [5.9 L]

Nutrition MISTAKE
Thinking that….
 Sports drinks are only needed for exercise lasting
more than an hour
Not always true if the activity is intense & occurs in
hot, humid conditions
 Sports drinks actually drive thirst
 Very easy way to improve performance, fight
dehydration, and decrease recovery time

Sport Drinks – per 8 oz serving








All Sport
Power Ade
Gatorade
HFCS
20g
HFCS
19g
sucrose/
15g
glucose
PR*Solutionfructose
30g
maltodextrins/
Succeed Ultra
sucrose/
14g
maltodextrins
Red Bull
sucrose/
28g
glucose
Coke
HFCS
27g
Orange juice
fructose/
29
glucose
8%
8%
6%
80 mg Na+
55
110
12.5%
50
6%
trace
12%
215
11%
12%
35
trace
WHAT ABOUT….
300mg caffeine!
Energy Drinks?
Different from Sports Drinks
 Contain caffeine, other stimulants, sugar, herbs and
vitamins
 Safety concerns for athletes!
 Use nutrition, hydration, and lifestyle changes to
improve energy level

Hyponatremia




Fluid/electrolyte disorder that occurs when Na level in
blood is below normal (<136 mEq/L)
Headache, malaise, confusion, swollen hands and feet,
wheezy breathing
Can lead to seizures, coma, death in severe cases
Potential causes include: Excessive sweating, excessive
Na losses in sweat, over drinking up to or during
event, replacing sweat losses with only H2O,
Intentional Urine Dilution (before drug testing)
Hyponatremia and Women




Women MAY be more susceptible than men
although the data is inconclusive
Females are more diligent drinkers
Female athletes are more likely to heed advice
(exceed?) from coaches, experts
One theory: Estrogen inhibits an enzyme
responsible for helping the brain shed excess
H2O
2007 Chicago Marathon





Exceptionally hot and
humid day for October
(88 degrees, 86%
humidity at 10 am)
Race was stopped at 3 ½
hour mark
250+ racers hospitalized
for heat related ailments
Water stations ran out of
water early
Very limited sports
drinks
Pre-Exercise Fuel
Pre-exercise fuel should:

Provide energy to working muscles
Maximize blood sugar and glycogen stores
Provide a psychological edge
Minimize hunger during play
Maximize hydration

Be individualized




Pre-Exercise Fuel




Meals should be 2/3 normal size
Meals: 3-4 hours before competition
Snacks: 1-2 hours before competition
The closer they are to competition, rely more on
liquids and small snacks
CHO AMOUNT RECOMMENDED



1 hour before 0.5 gm CHO/#
2 hours before 0.5-1.0gm CHO/#
3-4 hours before 1.0-1.5gm CHO/#
Carbohydrate guidelines


Pre-event  1-2 g/kg 1-2 hrs prior or 45 g/kg 3-4 hrs prior
During 1 g/min later in exercise or
40-65 g/hr or .5-1.0 g/kg/hr


Sport drink
After  .75-1.6 g/kg/hr
Timing of protein & carbohydrate
To enhance protein synthesis in muscle and replace
glycogen stores…
 Don’t exercise in fasted state
 Eat immediately after exercise [window of opportunity]

~ 6-8 g protein + 1-1.5g CHO/kg BW within 30
minutes [1 oz meat, 1 c milk, 1 Power Bar, OR 1/2c
mac & cheese + ~ 50 carb]
 6-10g CHO/kg BW per 24 hours
Recovery

Defined: Helping athletes bounce
back for future exercise bouts

Considerations
 Intensity of exercise
 When will athlete exercise again?
Nutrition Recovery Goals:
Glycogen restoration
 Fluid & electrolyte replacement
 Muscle repair and adaptation

Refueling after Exercise


VERY Important for Athletes

For those in multiple events in one day

For those training daily
“Window” for Refueling


First 30 minutes after exercise is critical
Glycogen repletion occurs faster after exercise
Increased blood flow to the muscle
 Enzymes that produce glycogen are most active

Refueling after Exercise
Facts:
 Muscles replace glycogen @
5% /hour
 20-24 hrs post exercise to
maximally replenish glycogen
stores
How?
 0.5 g / kg CHO immediately
after activity
 0.5 g / kg CHO in next 90
min.
 Rest
Nutrition MISTAKE
Thinking that….
 Sports shakes, bars, and drinks can replace a
balanced diet


Sports foods can provide an effective, convenient method for
the athlete to boost his/her nutrient needs during training
and competition.
Missing key nutrients including phytochemicals, antioxidants,
and fiber.
Bigger
and Stronger
1950
1975
2000
Average Height
Of pro BB player
6’3”
6’5”
6’7”
Average weight
Of pro FB player
209#
225#
244#
Source: ESPN
In the recent media….

Over 50% of the 2100+ active NFL players
were “obese” with a BMI over 30 (2004)
JAMA 2005
 No body comp, data taken from websites


40% of top high school football recruits
weighed in >300 pounds

Scripps Howard News Service 2006
Yet,
What do we do for the BIG Guys?





EDUCATE them about increased risk for heat
illness, asthma, future obesity, cardiac death
Emphasize gain LBM
Assess body composition, performance
parameters, injuries
Teach that bigger is not necessarily better (OK if
genentics support)
Make health a priority or at least on the radar
First Things First…



Must eat breakfast everyday
Eat every 3-4 hours to keep
blood sugar level
Stay hydrated through day
If we could give every
individual the right amount
of nourishment and
exercise, not too little and
not too much, we would
have found the safest way
to health."
Hippocrates c. 460 - 377 BC
Download