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Nutrition to beat the competition
For the modern athlete,
nutrition is taken as seriously as the
training
program. There are no shortcuts or false starts to a winning
diet- the answer lies in
balancing
intake with output.
 The
physical and psychological benefits of
exercise are undeniable but, when strenuous
physical
exercise is part of your daily life, you must make sure that you
are eating the right
diet
for long-term health. Athletes have similar
nutritional
requirements to those of the average person but, because of
physical exertion, they may have increased
carbohydrate needs. An endurance athlete’s diet may consist of
up to 67 per cent carbohydrate.
Athletes should be wary of
manipulating their diet to achieve short-term performance at the
expense of lifelong health. No single food can magically
enhance performance; only a good
range of foods can enable an athlete to compete in peak
condition. When a sports activity demands a high energy expenditure,
an adequate intake of calories, macronutrients (carbohydrates,
proteins,
fats and
fiber), and micronutrients (vitamins,
most
minerals and trace elements (is essential to maintain energy and
fluid balance).
Athletes should follow a balanced diet
which is ‘scaled up’ to meet increased energy needs. Contrary to
popular opinion, there is no need to eat a
high-
protein diet when undergoing training; in most cases it is
better to obtain extra calories from carbohydrates, although
athletes with very high energy demands, such as oarsmen, need a
greater than average intake of
fat so that the diet is not too bulky. However, some less
energetic sports- snooker for example- do not require any increase
in calories.
THE FLUID FACTOR
 During
physical exercise,
breathing
out and sweating deplete the body’s reserves of fluids. Excessive
perspiration can lead to a reduced flow of blood to the extremities,
a reduction in blood volume and, in extreme cases, to dehydration,
heatstroke and collapse. Therefore it is vital to drink water
before, during and after exercise.
Commercial ‘isotonic’ sports drinks
contain low levels of salts (to induce thirst and to replace
minerals lost through sweating) and sugars for energy. Since these
drinks are designed to prevent dehydration, they are not retained in
the stomach and pass quickly into the small intestine for
absorption. A cheap substitute is to dilute fruit juice 1:1 with
water.
 MORE MINERALS
The mineral content and requirements
of tissues and cells differ. Bone contains a lot of
calcium; muscle cells contain large amounts of
potassium and
magnesium, while blood carries high levels of sodium and
chloride. A shortage of minerals will normally be compensated for by
reduced excretion or by the release of some of the minerals stored
in the body’s tissues.
If you
run a marathon and are temporarily depleted of minerals, these will
probably be restored without you making any changes to your diet,
but prolonged mineral deficiency can be serious. Some authorities
advise the use of multi-mineral
supplements,
although there is no scientific proof that these significantly
improve the performance of athletes.
The potassium in muscles is gradually
lost as they work repeatedly during exercise. The body needs this
mineral for the release of
energy,
a
regular heartbeat and movement of digested
food. Replenish stores by including plenty
of potassium-rich foods in your
diet; good sources are lean meats, vegetables, nuts, pulses and
fruit-especially bananas.
 Low magnesium levels have often been
found in athletes engaged in endurance exercise. When too little
magnesium is available for use it can interfere with the release of
energy, causing fatigue and possibly muscle cramps leading to poor
muscle tone. Foods rich in magnesium include seafood, dark green
leafy vegetables, whole grains, nuts and pulses.
Much of the zinc in our bodies is
stored in bone and
muscle;
only a small amount is readily available, mainly in the blood.
Zinc is lost primarily through urine and sweat, so athletes need
to watch their daily intake. Good sources include seafood, offal,
eggs, wheatgerm and pulses.
ANAEMIA IN FEMALE ATHLETES
 Although the exact
reasons are not fully understood, female athletes are known to be at
risk from
anaemia. It is important, then, that they should have an
adequate intake of
iron,
folate
and
vitamin B12 to support normal blood formation. Good dietary
sources of iron include red meat, offal, egg yolks and dark green
vegetables.
Folate
can be obtained from liver, wheatgerm, cabbage, pulses, broccoli and
yeast extract, while sources of Vitamin B12 include offal, poultry,
fish, eggs and dairy produce.
LOOK AFTER YOUR BONES
 Almost
all the body’s calcium is in the bones: 1 per cent is available
elsewhere in the body, and may be lost through sweating.
Bones, despite
their deceptive hardness, constantly need to absorb and release
calcium
and, when calcium intake is low, bones become weaker. Ensure that
the diet contains adequate calcium by taking plenty of milk and
other dairy produce, as well as green leafy vegetables.
Young women athletes, especially
long-distance runners, are particularly susceptible to reduced bone
density or
Osteoporosis, when exercise,
stress and
weight loss leads to depressed oestrogen levels, resulting in
irregular or missed periods and inefficient calcium metabolism. This
probably a consequence of the very low levels of
body fat that
the runners strive to maintain. Tennis players and swimmers are less
likely to have problems because they usually have more body fat.
Women who take regular, medium-impact exercise-such as
walking or
jogging in good sports shoes-can take heart, as this type of
exercise actually lowers the risk of osteoporosis.
GLYCOGEN: THE MUSCLE FUEL
Glycogen is the main fuel the muscles
use when they move. It is produced form the glucose provided when
carbohydrates are digested, and is stored in muscles and in the
liver. Unfortunately, the body can store only a relatively small
amount of glycogen, so athletes need a
high-carbohydrate diet to make sure glycogen stores are always
full before any activity.
BEAT THE FATIGUE WALL
 When glycogen
stores are exhausted, for instance during a marathon, an athlete
hits the ‘wall’ of fatigue and feels too exhausted to continue the
event. Gradually increasing training in the run-up to an event,
while maintaining a diet high in complex carbohydrates, such as
potatoes and rice, can increase the period of efficient performance.
Some athletes used to prepare for major events by ‘carbo loading’,
that is: cutting down on carbohydrate- rich foods for several days,
and then overloading with foods such as
bread and
pasta for two or three days immediately before an event. These days
most athletes keep to a diet high in complex carbohydrates all the
time.
WHY FATS ARE NEEDED
 Because the
emphasis in an athlete’s diet is on a high carbohydrate intake,
fat intake
need only make up about 30 percent of calorie intake. Muscle uses
fat as its preferred fuel during light exercise, but
carbohydrate
is used up faster at higher levels of activity. A high carbohydrate
intake can improve endurance, but it makes for a very bulky diet.
Adding fat to food can double its energy value without adding too
much bulk. When adding fat to the diet,
unsaturated
fats (found in vegetable oils and oily fish) are healthier than
saturates
(the hard fats in cheese, butter and meat) and the Trans fatty acids
(present in most margarines). However, you should not attempt to
exclude all saturated fats from the diet.
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