FOOD MATTERS!
When you exercise, your body must start producing energy
very much faster than it does when it is at rest. The muscles start to contract
more strenuously, the heart beats faster pumping blood around the body more rapidly
and the lungs work harder. All these processes require extra energy. Where does
it come from and how can you ensure that your swimmers have enough to last
through a training session?
Where does energy
come from?
Energy comes from the food that they eat. There are three components of food and drink that are capable of producing energy:
·
Carbohydrate
· Fat
·
Protein
When you eat a meal or have a drink these components are
broken down in your digestive system into the various building blocks. Then
they are absorbed into the bloodstream. Carbohydrates are broken down into
small single sugar units; fats are broken down into fatty acids; and proteins
into amino acids. Alcohol is absorbed directly into the blood.
Carbohydrates are used mainly for energy in the short term,
while fats are used as a long term energy store. Proteins can be used to
produce energy in 'emergencies' (e.g. when carbohydrates are in short supply)
or when they have reached the end of their useful life. Sooner or later, all
food and drink components are broken down to release energy.
What is fatigue?
Tiredness! Fatigue during exercise can be experienced in
many forms. Your swimmers may find it harder to swim certain times at the end
of a session, or it may become harder to concentrate on technique, or they may
find that they are unable to swim with good technique because they have lost
co-ordination. This is fatigue!
How can fatigue be
delayed?
Your swimmers can help to delay fatigue in the following ways.-
·
Start
exercising with full energy (glycogen) stores
Think of it like setting off on a car journey with a full tank of petrol. The more they have to start with, the longer they can keep going. If they start with only half a tank of petrol, they will either have to stop halfway, or go more slowly to conserve your fuel.
·
Reduce the
rate at which they are using muscle glycogen (energy)
The rate at which
they use glycogen depends on the type and intensity of the exercise, their
fitness level and the surrounding temperature. Exercising in
hot conditions uses up more energy. Try and get them to pace themselves
- if they start out too fast then they may run out of fuel before the end of
the session!
How does diet help to
delay fatigue?
A diet that is rich in carbohydrates will ensure high
glycogen (energy) stores. Remember that glycogen is made up of glucose that
comes from the carbohydrates in their diet. If they eat a high carbohydrate
diet, their glycogen stores are more likely to be full. This will help them to
exercise for longer and help them perform at their best.
The general consensus is that you should get approximately 60-70% of your energy from carbohydrates. In practice, to achieve this all meals and snacks should be based around foods which are high in carbohydrates. Carbohydrates are sometimes divided into two types: Simple (sugars) and complex (starches and fibres). Examples of these are shown in the table below-.
High in simple
carbohydrates |
High in complex
carbohydrates |
A mixture of simple
and complex |
Sugar (white and brown) |
Flour (brown and white) |
Cakes |
Jam, honey and other preserves |
Bread (all types) Pasta, rice, noodles |
Biscuits Puddings |
Fruit (fresh, tinned and dried) Soft drinks |
Oats and other grains Unsweetened breakfast cereals |
Sweetened breakfast cereals (Frosties
etc.) Sweet pastries |
Yoghurt Fromage frais |
Pulses (beans, lentils, peas) |
Pies Flans |
Sweets, chocolate |
Potatoes |
Cheesecakes |
Ice cream, Jelly |
Parsnips |
Bananas |
Milk |
Sweetcorn (unsweetened) |
|
One type is not necessarily better than the other is. Different carbohydrates are suitable for different circumstances. Carbohydrate foods that contain a range of other nutrients should make up the main part of the diet. In general foods rich in complex carbohydrates e.g. breads and grains and the naturally occurring simple carbohydrates e.g. fruit and milk have a better nutritional value than foods rich in refined simple carbohydrates e.g. soft drinks, sweets and chocolates. In practice therefore your swimmers should aim to get most of their carbohydrates from foods providing a good nutritional package, i.e. bread, grains, cereals, starchy vegetables, pulses, fruit and dairy products.
What carbohydrate to
eat and when?
|
Before exercise |
During exercise |
After exercise |
Between sessions |
How much? |
50g |
30-60g |
1g/1 kg body weight |
60% of energy |
Time period |
5-30 minutes |
Begin after 30 minutes; regular intervals |
0-2 hours |
Minimum 4-6 meals/ snacks (for twice daily training) |
Gl* |
High |
High |
High |
Low-moderate |
Examples |
· 2-3 bananas · ½ pt isotonic sports drink & 1 banana · 3oz dried fruit · jam sandwich (2slices bread with 2tbsp jam) ·
1 energy bar |
· 1 litre diluted squash (3-6%) · 1 litre sports drink · Energy bar · 2-3 bananas ·
2-3oz dried fruit |
· Banana sandwich · 3oz raisins · 4-5 low fat biscuits · 250ml glucose polymer drink (20%) ·
8oz potato |
· Pasta with lentils/ low fat cheese /chicken/fish · Rice with beans · Noodles with chicken · Beans on toast ·
Potato with tuna/ cottage cheese |
Gl* is the Glycaemic Index of food and it is a measure of the speed of carbohydrate absorption and the rate of the resulting rise in blood sugar.
Eat a balanced diet!
In theory your swimmers should be able to get all the vitamins and minerals they need from a well planned diet. This should include a wide variety of foods from each of the main food groups in the proportions outlined below:
Foods |
Number of portions
per day |
Cereals and starchy vegetables |
5-11 |
Fruit and vegetables |
5 or more |
Milk and dairy products |
2-3 |
Meat, fish and vegetarian alternatives |
2-3 |
Oils and fats |
0-3 |
Eat less of the
following:
(These foods are high in fat but relatively low in other
essential nutrients)
·
Butter, margarine and other spreading fats Fried
foods
·
Fatty meats and processed meat products (e.g.
sausages, burgers, meat pies)
·
Pastry dishes
·
Cakes and biscuits Chocolate
· Crisps and similar potato/com/wheat snacks
Make the following
substitutions:
(These foods provide some fat together with other essential
nutrients)
·
Semi-skimmed or skimmed milk instead of full fat
milk
·
Low fat spread or peanut butter instead of
butter or margarine
·
Low or reduced fat cheese instead of ordinary
cheese
·
Jacket or boiled potatoes instead of chips
·
Chicken, fish or lean meat instead of fatty
meat, burgers and sausages
·
Crackers, rice cakes or fruit bars instead of
crisps, biscuits and cakes
·
Fresh fruit instead of chocolate
Make the following
changes:
(These will reduce fat intake while supplying other
essential nutrients)
·
Limit frying to stir frying with limited amounts
of oil
·
Top baked potatoes with fromage
frais, yoghurt, half fat creme
fraiche or baked beans
·
Remove skin from chicken or turkey
·
Grill, bake stir fry or boil instead of frying
·
Choose lean cuts of meat and trim off as much
fat as possible