Have you ever gained 22 pounds in 11 hours? Have you ever dramatically improved your strength in a single day just from changing your diet? Well I have. In my last Bodybuilding.com article I detailed my bulking diet and how I followed up a carbohydrate depletion period with a day where I consumed only fruit juice to create a glycogen supercompensation effect.
So What Is Glycogen Supercompensation?
Glycogen supercompensation is when your muscles are able to hold a greater amount of glycogen than they normally would be able to. They will not only appear fuller and more pumped, but they will also have plenty of fuel to work hard.
Muscles need energy to contract. The muscles use ATP for energy, but ATP stores are quickly depleted. At first the body will create ATP by having creatine phosphate donate a phosphate molecule to ADP, but creatine phosphate is also depleted quickly. For the muscles to continue to work over longer periods of time, ATP must be created from muscle glycogen through glycolysis. Therefore, the more glycogen the muscles can hold, the more ATP can be produced for anaerobic muscle contraction. 
So now that we see how glycogen supercompensation can positively affect appearance and workout intensity, how do we cause our muscles to hold more glycogen than they normally would? By depleting the muscle glycogen stores our bodies will adjust by more readily creating and storing glycogen for perceived future shortages. Simple, deplete the muscles of glycogen, and they will more readily store glycogen.
Since carbohydrates are the body's main source for creating glycogen, glycogen depletion is best achieved by cutting carbohydrates out of the diet. The body can also create glycogen from protein and fat, but it is not as efficient at doing so. Glycogen is further depleted through working out since it is the body's preferred source of energy.
Once the muscles are depleted of glycogen, glycogen supercompensation can be achieved by simply consuming carbohydrates. Since the muscles will now readily hold glycogen, they will immediately create glycogen once the carbohydrates are broken down into glucose. The more quickly the consumed carbohydrates can be broken down into glucose, the quicker glycogen stores will be replaced. Therefore, simple sugars such as dextrose and glucose would fill glycogen stores the quickest. Carbohydrates that are lower on the glycemic index will still fill glycogen stores, it will just take longer and the glycogen supercompensation effect will be more gradual.
Why Does It Work?
Glycogen normally draws water into the muscle, so if carbohydrates are consumed without excess water, water from underneath the skin will be pulled into the muscle. This is why bodybuilders who use glycogen supercompensation for a full, dry appearance at a competition normally choose dry carbohydrate sources.
During the all-juice day of my bulking diet we are trying to refill glycogen stores as quickly and as fully as possible, therefore simple sugars with no added fiber, protein, or fat will get the job done more efficiently. Muscle building is also more efficient when the body has plenty of water to work with and is not dehydrated, that is why fruit juice is the optimal source of carbohydrates in this situation. Drinking water mixed with dextrose would also be a viable option, but I feel using fruit juice is healthier and more bearable.
So there you have it, a complete breakdown on glycogen supercompensation. How or whether you use it is up to you.
Ian is available for personal training at Lifestyle Family Fitness locations throughout the Tampa Bay area. He is also available for online nutritional consultation regardless of where you live. You can contact Ian at imatthew@tampabay.rr.com.