PART 1: CARBOHYDRATES
The entire energy system is fuelled by 3 classes of food called macronutrients. These nutrients are better known as:
Each of these nutrients are important, not only to fuel athletic performance, but also for overall health and wellness.
Although carbohydrates received a bad reputation in past and present to come, it stays the most important type of fuel to the general population but especially to the active population and athletes.
Athlete corner: Carbohydrate functions
During short intense sessions of exercise, carbohydrates are the ONLY fuel source capable to produce energy and supply the body quick enough. In fact during the first few minutes of any activity, it is carbohydrates that, almost exclusively meet the energy demands. In addition the ability to repeat a sprint or intensive repetition at the end of a game/race/workout, to the same high level as the start relies, in part, on the body’s carbohydrate system.
During prolonged lower intensity activities the main energy source is produced from fat, however carbohydrates acts as primary catalyst for fat to be broken down to energy. Therefore fat can only be broken down in the presence of a positive carbohydrate store.
Finally, carbohydrates play a vital role in central nervous system function. The brain exclusively relies on glucose (for carbohydrates) to fuel brain activity.
Types of carbohydrates
There are different types of carbohydrates. Understanding what they are and how they affect the body is important to the active population or athletes in terms of what they eat before and after games/training.
Three classes of carbohydrates exists:
Monosaccharaides is the most basic unit of carbohydrates and includes Glucose (blood sugar), Fructose (fruit sugar) and Galactose (milk sugar). Glucose can directly be used as energy while Fructose and Galactose need to be converted to Glucose in the liver. All monosaccharaides produce energy rapidly.
Disaccharides includes Maltose (Glucose+Glucose), Lactose (Galactose + Glucose) and Sucrose (Fructose + Glucose). All of which should be first broken down into single form and then converted to Glucose. Still this is a rapid source of energy.
Monsaccharides and Disaccharides are called simple sugars in their collective form. These simple sugars are essential to athletes for rapid energy releases and should be taken prior to high intensity short duration sessions or even prior to high intensity sessions with a longer duration IF a simple sugar (high GI) could be consumed half way. MOST important is to consume simple sugars as fast as possible after completing a game/race/workout to completely recover glycogen stores for optimal recovery.
Polysaccharides (complex carbohydrates) includes starch, fibre and glycogen. This is a combination of +100 monosaccharides and takes much longer to break down to its glucose form. Therefore it supplies energy steadily over a longer period, it also has a smaller, stablizing effect on bloodsugar levels. Athletes competing in lower intensity endurance events or workouts will benefit from complex carbohydrates for prolonged energy. Even higher intensity prolonged workout should benefit from complex carbohydrates if a snack is not possible during workout.
An average person has 2000cal (500g) stored carbohydrates. However an overnight fast (8h) or low carb diet could drastically deplete these store where a carbohydrate rich diet could easily double it. Therefore keep in mind that carbohydrate stores has a big capacity but are limited to an extent. A large amount of carbohydrates at once could exceed the limit and excess will be stored as fat. Therefore rather consume smaller amounts more frequently.
|Category||g/kg body weight (BW)|
|Weight loss||1.5-2/kg BW per day|
|Weight maintenance||2-2.5g/kg BW per dag|
|Light exercise (low intensity/ skill based activities)||2-3g/kg BW per day|
|Moderate exercise (1h/day)||3-4g/kg BW per day|
|Moderate-high exercise (1-3h/day)||4-6g/kg body weight per day|
|High intensity/volume exercise (3-4h/day)||6-8g/kg BW per day|
|Very high intensity/volume (elite athlete training >4h per day||8-10g/kg BW per day|
Aim not to limit carbohydrates below 1g/kg BW per day. Choose fibre-rich polysaccharides (complex carbohydrates) that has a low glyceamic index. Eat smaller portions of carbohydrates, frequently and have your fat portions with carbohydrates to decrease the effect on blood glucose (sugar) levels.
Next time glycaemic index is our topic of discussion. Looking forward to our next session.