Sport Nutrition Education Series

No. I
No. III
No. VI

No. II
No. IV
No. VII

Sport Nutrition Education No. V - Maximise Your Energy Store for Competition

Carbohydrate = Energy

Carbohydrate is the source of energy for an athlete, like gasoline for an automobile. Carbohydrate is metabolised into glucose in the body. Glucose maintains blood sugar at normal levels, is the energy for the brain and can be stored as muscle glycogen. Athletes can maximise muscle glycogen storage by increasing dietary carbohydrate intake. This is called "Carbohydrate Loading".

Carbohydrate loading is suitable for events which last longer than 90 minutes, like cycling, marathon, triathlon, and events which have more than one game in a day, especially those which game time is long or unpredictable, like windsurfing, badminton, soccer, squash, tennis etc.

However, carbohydrate loading is not suitable for short and power-related events, like short putt, high jump, sprint, weight lifting, shooting, bowling etc.

Where is the glucose stored?

A sedentary person has 13 grams of glycogen per kilogram muscle, but an athelte can have 32g glycogen/kg muscle. Carbohydrate loading can increase glycogen storage to 35 - 40 g/kg muscle. For example, a male athlete who weighs 68 kg would have:

Carbohydrate

Place of Storage

Function

350 g

Muscle

Supply energy to muscles

80 g

Liver

Maintain blood sugar

20 g

Blood

Supply energy to the brain

Carbohydrate Loading

Three days before the event, dietary intake of carbohydrate should reach 9 - 10g/kg body weight/day. For example, an athlete weighing 60kg needs to consume 540 - 600g carbohydrate. At the same time, training needs to be decreased to lower energy expenditure in order to maximise stores, or else muscle glycogen will be used during training and defeats the purpose of carbohydrate loading. Training adjustment should be decided by the coach. However, glycogen will be stored in exercising muscle group, therefore, a long distance runner should not be swimming three days before the competition.

A sample diet which consists of 550g carbohydrate and 2900kcal (suitable for an athlete weighing 60kg) :

Breakfast :

skimmed milk

1 cup

 

corn flakes

1 cup

 

banana

1

 

bread

1 slice

 

jam

1 tsp

 

Lunch :

rice

2 bowls

 

green vegetables

4 oz

 

chicken thigh

1 piece

 

soft drink

1 can

 

Afternoon Tea :

orange juice

1 cup

 

bread

2 slices

 

jam

2 tsp

 

Dinner :

rice

2 bowls

 

Chinese meat loaf

3 oz

 

green vegetables

4 oz

 

apple

1

 

red bean sweet soup

1 bowl

 

Evening Snack :

apple juice

1 cup

 

chiffon cake

1 piece

The following are examples of food containing 10g carbohydrates. Athletes may combine these in order to achieve the goal of carbohydrate loading (9-10g carbohydrate/kg body weight/day):

oatmeal (cooked)

1/3 cup

pasta (cooked)

1/3 cup

rice (cooked)

1/5 cup

soda crackers

2 pieces

bread

1/2 slice

corn flakes

1/2 cup

corn or green peas

1/3 cup

carrots (cooked)

3/4 cup

baked potato

1 (small)

baked beans in tomato sauce

4 tbsp

apple or pear or orange

1

kiwi fruit

1

banana

1/2

grapes

10

canned fruit

1/3 cup

orange juice

1/2 cup

milk or soy milk

1/2 cup

plain yogurt

60 g

horlicks powder

2 tbsp

soft drink

1/2 cup

For more information, please contact:

Sport Nutrition Unit

Telephone

(852) 2681 6277