Is Carbohydrate Loading for Bodybuilders Still a Valid Technique? by Jerry Brainum 6/25

 

 

Carbohydrate loading involves techniques to load the muscle with glycogen maximally. Glycogen is a complex carbohydrate that consists of long chains of glucose molecules. Each gram of glycogen is stored in the muscles with three grams of water. Glycogen is also stored in the liver, but that form of glycogen maintains the four grams of glucose circulating in the blood. While there is no dietary requirement for carbohydrates in human nutrition, glucose is the only carbohydrate form circulating in the blood. There is no dietary requirement for carbohydrates or carbs because the liver can produce glucose from other substrates besides carbs, such as lactate, produced during exercise and transported in the blood from the muscles to the liver. Glycerol comprises ten percent of the triglyceride or fat structure and can also be converted into glucose in the liver, as can specific "glucogenic" amino acids. Glycine, serine, aspartic acid, glutamic acid, glutamine, valine, methionine, histidine, and arginine are all glucogenic amino acids.

Although glycogen was discovered in 1858, the knowledge that it was a primary fuel for athletic activity emerged through research conducted by Swedish Sports scientists in the 1960s. Once they realized that muscle glycogen was the primary fuel to power athletic activity, the next step was to develop a system to maximize muscle glycogen storage. As such, the scientists developed what became known as muscle glycogen super-compensation or simply carbohydrate loading. The original carb-loading technique involved first depleting the muscles of stored glycogen, followed by a period of glycogen replenishment through a high intake of carbohydrates. This technique proved highly successful in promoting muscle glycogen stores that were considerably higher than normal. Having that extra glycogen stored in muscle made a big difference in helping to maintain energy during extended athletic events, such as marathon runs. Carb loading didn't take long to become standard practice among elite athletes. 

The one drawback to carb loading was the increased intramuscular water retention with glycogen loading. Since each gram of muscle glycogen is stored with three grams of water, increasing muscle glycogen levels to higher than normal levels led to an inevitable weight gain. However, the considerable gain in energy more than compensated for the slight weight gain that resulted from carb loading. Soon after carb loading became standard practice among endurance athletes, it attracted the attention of competitive bodybuilders. No one knows who came up with the idea of bodybuilders engaging in carb loading, but it did make sense for bodybuilding purposes, especially for contest preparation. Although glycogen comprises only 4% of muscle's total weight, the water it's stored with adds bulk to muscle and provides the impression of fuller and larger muscles.

Knowledge of the effect of larger glycogen stores in muscle led to the adaptation of carb loading for bodybuilding . . .