Athlete and the Carbohydrates
A diet high in carbohydrates is particularly important for the athlete. Carbohydrates are made up of sugars and starch and they should be the major energy providers in your diet. Everyone store very little glucose in the body so it is vital to have a regular intake of starch. This is because starch is converted to glycogen and stored in the liver and muscles. This glycogen is then used to meet muscles' energy needs by being converted back to glucose when the muscles exercise.
Starch is a highly important nutrient in the diet and is the body's favourite "fuel". It is important because it provides most of our glucose, which is the only fuel the brain can use. In addition, starchy carbohydrates contain fibre and are very good at satisfying our appetites.
If the muscles run out of glucose they can also burn body fat, but fat is not as efficient an energy source as glucose.
The following are some rich sources of starch :
Sugar is available in many forms and they are :
glucose - found naturally in fruit and vegetable juices
fructose - occurs naturally in fruit and vegetables and especially in honey
lactose and galactose - found in milk
sucrose - occurs naturally in sugar cane and sugar beet
maltose - available from fermented grain products
For the athlete, carbohydrates should provide 60 percent to 70 percent of total dietary energy (calories). Most of this coming from starch.
Simple sugar is not a good source of energy as it can upset the body's metabolism.
The general recommendation is that carbohydrates should supply a minimum of 47 percent of dietary energy (calories), but it is important for athletes to increase this. They should have a minimum of 60 percent to 70 percent.
Eg: If your total calorie intake is, say, 3,000 calories/day. Then calories from carbohydrate is 3,000 X 60 percent = 1800 calories
1 gram of carbohydrate = 4 calories
Therefore, 1,800 calories is equivalent to 450 grams of carbohydrate.
You should be eating an amount that enables you to maintain your weight within its healthy range.
Carbohydrate intake while exercising
Glucose, itself, is not stored in the body. Once the available glucose in the blood stream and cells' plasma is used up, the body then turns to its supply of glycogen. As mentioned earlier, your body has limited stores of glycogen in muscles and liver ready for conversion to glucose. So, it is likely that for longer exercise sessions - say, more than an hour - you are going to deplete your supplies of glycogen and, therefore, run low on glucose.
Probably the best way to top up while actually exercising is with an isotonic sports drink as this will provide glucose, fluid and also sodium. An intake of between 30 grams to 60 grams of carbohydrate an hour is recommended. This is about the maximum your muscles can take up from the bloodstream during exercise. Greater amounts have no further benefit. It is best to start taking in carbohydrate soon after the exercise session begins because of the delay in absorption.
Carbohydrate intake after exercise
This depends on: how depleted your stores are after the exercise session, your fitness level, the amount of carbohydrate you eat, and the extent of muscle damage.
It is best to replenish depleted stores of glycogen by taking in carbohydrate as soon as possible after your exercise session. During the first two hours, replenishment is most rapid and is approximately one and a half times the normal rate. During the following four hours, the rate slows down but remains higher than normal. Following this period, glycogen manufacture returns to the normal rate.
Restoring your glycogen levels as quickly as possible is very important, particularly if you train every day or every other day. This will help you avoid fatigue and get the best out of your training.