Glycogen: Premium fuel for exercise and sports by Jerry Brainum

The primary focus of bodybuilding nutrition is on protein. This makes sense since protein is related to increased muscular size and strength. The main controversies about protein are precisely how much to ingest to promote maximal muscular growth and whether or not large amounts of protein can be hazardous to health. Recent studies clearly show that those who are engaged in exercise or sports do need to ingest greater amounts of protein. As for the side effects, the common critiques include such assertions that large amounts of protein can harm the kidneys; protein can promote dehydration; and that too much protein promotes increases in body fat. All of these notions have been thoroughly discarded by solid research. If you have pre-existing kidney disease, it's a good idea to limit protein intake since the kidneys are responsible for the excretion of amino acid waste products, mainly urea. This does not present any problem to those with normal kidney function but could place added stress on those with existing deficits in kidney function. If you drink enough fluids, protein will not promote dehydration. As for the body fat, recent studies with bodybuilders who consumed over 5-times the suggested protein requirement for those engaged in exercise found that even that amount of protein did not cause any fat accretion at all.

As such, the controversies about protein aren't really that controversial. But when it comes to carbohydrate intake, the picture is far different. With the rising popularity of low carbohydrate diets, especially ketogenic diets that virtually eliminate most carbohydrates, the question that emerges is how necessary are carbohydrates for those involved in weight training? As far as endurance sports, such as long-distance running, there is no controversy at all. A higher intake of carbohydrates is an absolute necessity if you engage in endurance sports. Anyone who has viewed a marathon race, such as that shown during the Olympic games, is familiar with the sight of some runners who just seem to burn out before they reach the finish line. This is known as "hitting the wall," and is caused by a combination of dehydration and depletion of glycogen in muscles. The key to success in endurance sports involves tapping in body fat stores while minimizing the use of muscle glycogen. Glycogen is stored in the body in the liver and muscles, but only in limited amounts. Despite this, glycogen is without question the most efficient fuel for anaerobic exercises, such as weight training and any other type of high-intensity exercise.

What exactly is glycogen? Glycogen is a type of complex carbohydrate consisting of large branched chains of glucose. The liver can convert stored glycogen into glucose, which is then delivered to the blood for use as an energy source. However, glucose itself is not the most elemental form of energy used . . .