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Food and fluids can have a great
effect on the way we feel and on the ability of
the human body to perform repeated bouts of intense
physical exercise. It is only when coupled with
the correct form of training that diet can help
improve and maintain optimum performance. Our choice
of foods or 'diet' is one of the many important
choices we all have to make.
Food choices are unique to each individual and
depend on many factors such as availability, time,
personal likes, along with mood and other psychological
factors.
We believe the main dietary
considerations are related to the following:
- Provision of carbohydrates to provide energy.
- Maintenance of fluid balance.
- Control of body fat.
An understanding of the body's individual requirements
and some nutritional knowledge enables athletes
to select their own individual diet from the wide
variety of foods available to us today. One way
of assessing both individual foods and diets, is
to compare the amount of energy (kcal) provided
by carbohydrate, protein and fat. These figures
can be expressed in terms of a percentage of the
total energy in the food or diet.
Recommended percentage
energy breakdown are as follows:
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Normal
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Athlete
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Carbohydrate
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50%
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50-60%
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Fat
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<35%
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25-35%
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Protein
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10 to 15%
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10 to 15%
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These figures are guide-lines
only. There is no single correct diet.
Some athlete chose to eat foods which
have too much of their energy from fat and not enough
from carbohydrates. Many individuals however, seem
to have the balance about right.
Percentage Energy Calculations
For an individual food the calculation is
very easy to do since the information needed can
usually be obtained from the nutrition label on
a food. You first need to know the amount of energy
in a gram of each of the nutrients. This is expressed
as either kilocalories (kcal) or kiloJoules (kJ).
Strictly speaking, we should use the System International
(SI) units of kiloJoules, but in some countries
we tend to use kilocalories. (carbohydrate=4kcal/g,
protein=4kcal/g, fat=9kcal/g).
To calculate the figures for one day's food
you need to keep a food diary, recording the weight/portion
size of each food eaten. Using food tables or a
suitable computer program and the label information,
you then add up the total weight of each nutrient
(carbohydrate, fat and protein) eaten during the
day. You also calculate the total kilocalories in
the day's food.
- Multiply the nutrient weight in grams by the
correct factor to give the amount of energy from
the particular nutrient you are dealing with.
- Divide the answer by the total energy in the
food (or day's diet) and multiply the result by
100 to give a percentage.
General advice is that the diet should be primarily
based on foods that contain vitamins, minerals and
starchy (complex) carbohydrates. These include bread,
rice, potato, pasta, cereals, fruit, dried fruit,
fruit juice and vegetables.
A typical pre-match meal would have most of the
energy from carbohydrate and little from fat. Choices
could include soup, bread, potatoes, low fat pasta
meals (not cheesy), baked beans, vegetables, salad,
lean meat, skinless chicken, grilled fish, fruit
and yoghurt.
For athletes doing large amounts of exercise it
is sometimes necessary to eat sugary (simple) carbohydrates
such as jam, syrup, honey, some biscuits, some cakes,
sugary fizzy drinks and cordial drinks are included.
These foods in general contain lower levels of vitamins
and minerals and therefore should not be the main
foods in anybody's diet.
Fluid intake should be high. This is because water
is the main transport medium within the body and
is vital for temperature regulation. In addition,
athletes often have high fluid losses due to sweating.
If an athlete wishes to lose bodyfat then they have
to be more selective with their foods. They must
still eat a high carbohydrate diet to provide the
energy for exercise but try to reduce their intake
of foods which contain fat and oil. These include
cheese, pastry, sausage, burgers, peanuts, crisps,
butter, margarine, some chocolate and some biscuits.
I hope that this brief summary will be of use to
you and that you enjoy learning about nutrition
as much as I do.
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