Carbohydrate Loading for Performance
How to calculate the right amount of Carbohyrates for you!
Why do you need carbohydrates?
To understand why you need carbohydrates, it’s important to know their role in energy production. There are 3 processes tasked with providing fuel for your muscles. Two of them are anaerobic (alactic & lactic systems) and have no oxygen requirement (think explosive movements over a short time-frame). The third system is aerobic and needs oxygen to function (slower movements over an extended period of time). Carbohydrates are needed in both the lactic-anaerobic system and the aerobic system. This is so they can respectively be broken down to lactic acid during glycolysis and combusted alongside of fats in the presence of oxygen (Gastin, 2001).
What type of exercise is carbohydrate loading most effective for?
Studies have shown that carbohydrate loading for anaerobic activity was not beneficial (Hawley, Schabort et al. 1997). The explanation for this, is that short bouts of activity will not deplete an athlete’s muscle glycogen. Another reason is that anaerobic activities require a significantly reduced contribution from carbohydrate-based energy systems (Gastin, 2001).
Aerobic exercise however, is another story! Carbohydrate loading before any strenuous activity in excess of 60-90 minutes can result in a delayed time to failure of up to 20%. This is a huge increase in performance and highlights the importance of a well-structured carbohydrate loading phase.
It’s important to note that ALL THREE systems contribute to your energy requirements during exercise, albeit the percentages will differ depending on exercise intensity (Gastin, 2001). This suggests that you should still try to have an abundance of all energy substrates for maximal performance.
How many carbohydrates should you be consuming? Formulate your loading-cycle:
The quantity of recommended carbohydrates during a loading-cycle will vary from individual to individual. Exercise type, intensity and total hours of activity are all factors which will affect recommendations, however the table below can offer some guidance.
This table was adapted from (Cardwell 2006).
Examples:
A high level, amateur sportsman (80kg), who trains 3 x week, lifts weights 4 x week, competes 1 x week and lives an active lifestyle:
= 80 (body weight/kg) x 6 (g/Carbohydrates)
= 480g of Carbohydrates per day.
An individual (70kg) who lifts weights 2-3 x week, walks the dog 3 x week but works long hours at a desk job:
= 70 (body weight/kg) x 3(g/Carbohydrates)
= 210g of Carbohydrates per day.
When should you start carbohydrate loading?
This question depends on your activity level or competition length. Some elite level athletes utilize high-carbohydrate diets year-round to ensure a plentiful supply of muscle glycogen. If your intension is to perform a carbohydrate loading cycle closer to competition, you should ramp up your consumption 7-days prior to competition with an emphasis on the final 48 hours (Cardwell 2006).
***Remember!!! These are just recommendations. Drastic increases of carbohydrate consumption in some individuals may lead to gut and gastric irritation, whereas others can eat more with no negative impact whatsoever.
Eat smart, train hard and perform at maximum capacity.
References
Cardwell, G. (2006). Gold Medal Nutrition. Champaign, IL, U.S.A, Human Kinetics.
Gastin, P. (2001). Energy System Interaction and Relative Contribution During Maximal Exercise | SpringerLink. Sports Medicine, 31(10), 725-741. doi:10.2165/00007256-200131100-00003
Hargreaves, M. (1996). "Carbohydrates and exercise performance." Nutrition Reviews 54(4): 4.
Hawley, J. A., E. J. Schabort, T. D. Noakes and S. C. Dennis (1997). "Carbohydrate-Loading and Exercise Performance." Sports Medicine 24(2): 73-81.
Written by Nevin Mills - The Strength Institute of Western Australia
