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Eating to Play
By Dr. Don Kirkendall
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A letter was sent to the editors
requesting information about eating
around game times. With the new season
nearly upon us, it is probably a good
time to review some topics associated
with nutrition and sports performance.
This has been one of the most intensely
researched topics in the sports
performance literature and there have
been many advances from the "Saturday
morning steaks" that dads might remember
from their high school football days.
Research can be grouped into four
categories regarding the timing of
eating: training days prior to
competition, day of competition, during
competition and after competition. In
brief, carbohydrates are the best choice
so choose foods that give the most
carbohydrate per serving.
Days Prior To Competition
This was the first real focus of study
that lead to the "glycogen loading"
concept. Without going into a lot of
scientific history, the typical routine
now is to gradually reduce training
volume and intensity while increasing
the fraction of the total diet that is
carbohydrates. This will help the
muscles load up extra glycogen (the main
fuel for muscles) for the game.
In soccer, this is not a common practice
unfortunately. Most research shows that
the muscle glycogen levels of (male)
soccer players are no better than the
spectators in the stands - not good.
Studies on soccer players have shown
that those with the most pre-game muscle
glycogen run the farthest at the fastest
speeds during a game. As such, it is
surprising to see that glycogen loading
schemes have not been as universally
adopted in soccer as they have in
traditional endurance sports like
running, cycling, cross-country skiing
and triathalons.
Five to six grams of carbohydrate per
kilogram of body weight over a 24 hours
period is the typical suggestion so read
those labels on food packaging.
Remember, 1 pound of body weight/2.2 =
kilograms of body weight.
Day of Competition
There is probably no more area full of
misleading information than eating the
day of competition - the proverbial
pre-game meal. Most pre-game meals are
eaten in the 3-4 hours prior to
competition. But realize that the food
eaten will have little to do with the
energy expended in the game. That comes
from what was eaten in the 2-3 days
prior to the game.
Most players eat what they like so they
won?t still feel full come game time.
Remember that the more calories (i.e.
fat and protein) in a meal, the slower
the food leaves the stomach.
Carbohydrates are always the best choice
as fruits, cereals, juices,
pancakes/waffles etc. over sausage,
eggs, steak, or many choices on the
breakfast menu at a fast food
restaurant.
Food in general, and carbohydrates in
particular, should be avoided in the
last hour before play. Carbohydrates
stimulate an insulin response which
lowers blood sugar and also stimulates
the production of serotonin, a chemical
in the brain that reduces arousal (makes
you listless and sleepy).
Both are obviously counterproductive to
competition. If something must be eaten,
choose low glycemic index foods as they
cause less of an insulin response.
Immediately prior to competition (in the
minutes before kickoff), carbohydrates
can be taken in. The excitement of the
game will counteract the insulin
response and the fresh carbohydrates
give the muscles an extra source of
fuel. The type of carbohydrates is
important. Foods should be of a moderate
or high glycemic index (see table).
Carbohydrate supplement drinks work
great. "Clear" candies (jelly beans,
"Gummy" candy, Skittles etc. you get the
idea) are another choice. .
Eating During Competition
During the game, carbohydrate supplement
drinks given before the game and at
halftime have been shown to increase
running volume and intensity in the
second half in soccer players. This is
important to consider because goals
become more frequent later in the game
as players get tired.
If you have more energy than your
opponents, you are more likely to have
an advantage over the opposition and
hopefully, score more later in the game.
As you can see from the table below, the
ubiquitous orange slices at halftime are
pretty low on the priority as a
carbohydrate source.
Eating After The Game
The game uses muscle glycogen
(carbohydrate) so it must be replaced.
Research has shown that muscle is the
most receptive for carbohydrate
replacement in the first two hours after
exhaustive exercise. Therefore, it is
important to eat some moderate to high
glycemic index foods in the first two
hours after a game.
From the table, you see there are quite
a variety of options for food, most of
which require a little planning and
typically do not come in a bag or a tray
from a fast food restaurant. With games
at 12 noon and 4 pm, it is necessary to
get some carbohydrates back into the
muscles quickly.
Remember, fast foods are high in fat and
protein and can remain in the stomach at
the start of the next game (depending on
when it was eaten and how much was
eaten) and doesn?t return much in the
way of carbohydrates to the muscles,
therefore should be avoided.
A nutritionist gave me a good
suggestion: make up bags of Chex Mix
with some pretzel sticks added (forget
the oil and baking requirement) and let
the players eat this after the game.
Clear candy is also good as are raisins,
cakes, pies, bagels.
Ideally, eat 50-75 grams of carbohydrate
every two hours until you reach the
total based on your weight (5-6 grams/kg
body weight).
But don?t get the idea that all the
carbohydrate can be replenished in a
couple of hours. Under the best of
conditions, it can take 20 hours to
fully replenish muscle glycogen from
muscles that have been completely
depleted.
Eating for sports performance requires a
bit of planning and clock watching, but
can lead to improvements in performance.
When done properly, the players will
notice they have more energy late in
games as well as when they have multiple
games with minimal recovery between
games.
For more information, try:
http://www.olympic-usa.org/inside/ -
USOC website for nutrition information
including some sample menus.
http://www.mendosa.com/gi.htm - a
complete discussion of the glycemic
index.
http://www.mendosa.com/gilists.htm - for
a long list of foods with their glycemic
index. These last two sites are written
for diabetics, but contain much useful
information.
Glycemic Index Table
High Glycemic Foods
Syrups (e.g. maple, corn, cane); Honey;
Bagel, white bread, jams, jellies;
Potato; Most cereals; Raisins, banana,
watermelon, pineapple; Carrots, cooked;
White rice; Maltodextrin; Jelly beans,
Skittles, pretzels, most candy bars
Moderate Glycemic Foods
Whole grain bread; Spaghetti; Corn;
Oatmeal; Oranges, grapes
Low Glycemic Foods
Yogurt; Peanuts; Beans, peas; Apple,
peach, pear; Milk and milk products.
This sports science article comes from
the Sports Medicine Section at the Duke
University Medical Center and UNC
Hospitals. The authors are members of
the US Soccer Sports Medicine Committee
including from UNC Dr. William E.
Garrett, Jr (US National Teams Physician
and Committee Chairman), and John Lohnes.
From Duke are Dr. Don Kirkendall
(exercise physiologist) and Patty
Marchak (athletic trainer for 1996 US
Women's Olympic Team).
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