Carbohydrates and Exercise

Unlike your body's fat stores which will provide an average 70kg individual with 72,000 Kcals of energy, your body's store of glycogen from carbohydrates can be depleted fairly rapidly, if adequate replenishment does not take place.
The depletion process is also cumulative and as the days of continuous exercise progress without adequate amounts of carbohydrates, the exercise sessions by the end of the week will become increasingly difficult as your body struggles for energy as your stores are almost depleted.
Some studies have also shown that running and weight training that can induce muscle damage can impair glycogen resynthesis (reloading) 6 to 12 hours after exercise. So the muscle repairing process actually inhibits the replenishment of glycogen to those exercised muscles depending on the severity of the workout.

Carbohydrate taken just before or during exercise either in the form of a drink or solids may actually improve your workout performance and has less of an impact on your blood sugar levels if it is consumed less than 15 minutes before a workout. This is the same for both simple and complex carbohydrates. It has been suggested that the body can absorb 50g of any type of carbohydrate in one sitting without any being converted to fat (as long as you have not eaten for 2 hours).

Here are some examples of 50g carbohydrate pre-workout snacks:

• 3 oz (75g) of dried fruit
• 2 slices of bread and a banana
• High5 Sports bar and a small banana
• 5 rice cakes and a banana
• 2.5 oz or 65g of a breakfast cereal
• 6 crispbreads with a tbsp. jam/honey/marmalade
• Half a serving of Prolab Advanced Mass2 drink mix
• 3 small bananas
• High5 Energy bar and a banana
• 8 rice cakes
• 3 oz plain or milk chocolate
• 2 pints of milk
• 3-4 apples
• 1 tin of rice pudding
• 7 oz of cooked pasta
• One serving of High5 Energy Source drink

Further Reading : -

Simple and complex carbohydrates....whats the difference?
Carbohydrates and exercise, why is it important ?
A more indepth look at carbohydrates.