Exercise and diet
Exersice and food
When you exercise, your body uses more energy than normal. Energy is measured in calories, so the more exercise you do, the more calories you will need to eat to replenish your energy stores.
Carbohydrate is the most important fuel for energy. It is stored in the liver and muscles as glycogen and if these stores run low, your muscles will not work as well as they should. This will result in tiredness and fatigue when you exercise.
In order to replenish your glycogen stores, you need to eat foods that are high in carbohydrate. Sugars and starch are the main dietary sources of carbohydrate. Sugary foods are not as beneficial as starchy foods – even though they are high in calories – because they contain very few nutrients and don't fill you up. This means that you may consume more calories than you actually need, which could lead to you putting on weight.
The amount of carbohydrate you need to eat will depend on how much exercise you are doing. If you only do a small amount of exercise each week, sticking to your standard balanced diet should be sufficient.
If you are more serious about sport, then the following table can help you work out how much carbohydrate you need to eat to replenish your energy stores.
| Activity | Recommended Carbohydrate Intake for Body Mass (BM) |
| Training programmes 1-1.5hours - low intensity | Daily intake of 5-7g per kg BM |
| Training programmes 1.5-2 hours per day | Daily intake of 7-10g per kg BM |
| Extreme exercise programme 6-8 hours per day (cycling tour) | Daily intake of 10-12+g per kg BM |
| Carbohydrate loading for endurance and ultra endurance events | Daily intake of 7-10g per kg BM |
| Pre-event meal | Meal eaten 1-4 hours pre-competition 14g per kg BM |
| Carbohydrate intake during training sessions and competition events greater than 1 hour | 1 g per min or 60g per hour |
| Recovery after training | Intake of 1g per kg BM in the first 30 min after exercise, repeated every 1-2 hours until regular meal patterns are resumed |
Example:
Stef runs 1 hour each evening, he weighs 78kg
78kg x 5g carbohydrate = 390g carbohydrate
78kg x 7g carbohydrate = 546g carbohydrate
Therefore, Stef needs to eat between 390-546g of carbohydrate per day
Foods providing 50g of carbohydrate include:
- 4 slices white or 3 thick wholegrain bread
- 6 large or 15 small crispbreads and dry biscuits
- 60g cornflakes/branflakes
- 1 large baked potato
- 2 soft white rolls
- 1 large can baked beans (440 g)
- 5 Shredded Wheat/Weetabix
- 2 large bananas
- 2 large pitta bread
- 400g can of kidney beans
- 65g muesli
- 3-4 medium oranges
We need protein for our muscles to grow and repair themselves. Protein is also a source of energy.
People who train frequently and are very active generally need more protein than people who don't. However, in the UK most people already eat more protein than they actually need, so even top athletes shouldn't need to increase their protein intake.
There is also no need to take protein supplements. Current research suggests that taking protein or amino acid supplements doesn't improve your performance when you train. With a balanced diet, you will get all the protein you need.
Keeping hydrated before, during and after exercise is extremely important because dehydration of as little as 2% of body weight (lost as water) will affect your physical performance.
Water has a number of important roles in your body:
- It acts as a lubricant for joints and eyes
- It helps you swallow
- It is important for the chemical reactions that take place in your body
- It helps to get rid of waste
- It helps to regulate body temperature.
Regular fluid intake is therefore essential for your body to work properly.
The amount of fluid you need depends on your age, the time of year, the climatic conditions, your diet and the amount of exercise you do. You will need to drink more fluid when you are in a hot climate and after you've exercised.
In the UK climate you should drink at least 1.5 to 2 litres of liquid a day. Water is good for replacing any lost fluid after mild or moderate exercise, but after vigorous or prolonged exercise, isotonic drinks are more suitable because they replenish both water and your glycogen stores.
Breakfast
Bowl of porridge topped with raisins
Glass of unsweetened fruit juice
Toast and honey/jam/marmalade
Snack
Fresh fruit
Dried fruit
Cereal bar
Slice of malt loaf
Lunch
Jacket potato with beans and grated cheese
Green salad with a vinegar/low-fat dressing
Snack
Pick a snack from the list above or try:
A sandwich with a low-fat filling such as chicken without the skin or low-fat cream cheese
A low-fat yoghurt and a piece of fresh fruit
A banana and low-fat custard
Pot of low-fat rice pudding
And don't forget to keep drinking; you could have some fruit juice or a smoothie.
Dinner
Bowl of pasta with tuna, vegetables and a tomato-based sauce
Fresh fruit salad
Supper
Bowl of cereal and low-fat milk or soup and roll
Reference
http://www.eatwell.gov.uk/healthydiet/foodforsport/sportnexercise/. Last accessed December 2, 2010
