2009 Studies & Research Blog

Common sense, as well as scientific studies, have established that pre- and post-workout nutrition are essential components to a training program.  Supplying your body with the fuel and the nutrients it needs before any type of exercise allows you to perform at a higher level.  Likewise, re-fueling tired muscles, reversing catabolism and initiating anabolism with a post-workout feeding benefits the pursuit of muscle mass.

Recently, intra-workout supplementation has gained popularity in the bodybuilding community.  The consumption of Branched Chain Amino Acids (BCAAs), as well as Citrulline Malate and even whey protein during lifting sessions is now commonplace.  However, it seems that intra-workout carbohydrate supplementation is less popular.  This is a shame, because carbohydrates can have beneficial effects when taken during training.

One study analzyed the performance of cyclists with or without the supplementation of carbohydrates.  The researchers found that cortisol levels were reduced, and time-trial performance improved, during trials with carbohydrate supplementation.  Interestingly, fat oxidation was significantly increased when carbohydrates and caffeine were supplemented together during the trials (1).

Critics of intra-workout carbohydrate supplementation argue that it reduces the body’s ability to burn fat during exercise.  However, research has shown that this is not necessarily the case.  Levels of fat oxidation were not significantly different and researchers concluded that during "moderate-intensity exercise," the feeding didn’t "suppress fat oxidation" (2).

Additionally, carbohydrates play a vital role when supplementing amino acids during exercise.  Researchers have noted that carbohydrates assist in "potentiating protein balance" and can help "meet the fuel needs of the working muscles."  Furthermore, carbohydrate consumption, with or without BCAA supplementation, "provides an effective strategy against both peripheral and central mechanisms of fatigue" (3).

Still, many critics will point out that the majority of the studies on this subject relate to endurance exercise.  However, research on carbohydrate supplementation has been tested in other athletic events, such as soccer, as well (3).

If you do choose to supplement carbohydrates during training, dosage is an important consideration.  Obviously, consuming too many calories during any kind of exercise will counteract the effects of the activity.  However, studies have indicated that 20 grams of carbohydrates can be oxidized in one hour of exercise.  While you may still be skeptical of carbohydrate ingestion for shorter workouts, researchers advised that during longer training sessions, there is "no doubt" that carbohydrates should be supplemented (4).

In the end, the decision whether or not to take in carbohydrates during training is up to you.  You should consider how these calories will fit into your overall fitness plan, and whether the duration and intensity of your training calls for additional nutrition.

SOURCES:

1. Slivka, Dustin, et al. Effects of Caffeine and Carbohydrate Use on Exercise Performance, Substrate Oxidation and Salivary Cortisol. Medicine & Science in Sports & Exercise, 2008; 40(5): S361.

2. Civitarese, Anthony E., et al. Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes. American Journal of Physiology, Endocrinology and Metabolism, 2005; 289: E1023-E1029.

3. Burke, Louise M. Branched-Chain Amino Acids (BCAAs) and Athletic Performance. International Sports Medicine Journal, 2001; 2(3): 1-7.

4. Dennis, S.C., et al. Nutritional strategies to minimize fatigue during prolonged exercise: Fluid, electrolyte and energy replacement. Journal of Sports Sciences, 1997; 15(3): 305-313.