Glycogen is a polysaccharide that serves as a form of long-term energy storage in animals and humans, similar to plant starch.
Glycogen is stored in the liver and muscle tissue and can be rapidly mobilized as a source of glucose when the body needs energy. Its primary function is to maintain blood glucose levels, which is critical for the functioning of the brain, muscles, and other organs and tissues.
Glycogen consists of hundreds and thousands of glucose molecules linked by glycosidic bonds.
When transitioning to a ketogenic diet, the body starts using glycogen as a quick energy source before the process of ketosis begins.
Once glycogen stores are depleted, the body enters a state of ketosis, actively using fats to produce ketone bodies that serve as an alternative fuel for the brain and other organs.
Even with strict adherence to the ketogenic diet, some glycogen can be replenished through gluconeogenesis – the process of generating glucose from non-carbohydrate sources such as lactate, glycerol, and amino acids.
For athletes following a ketogenic diet, it’s important to understand that their ability to perform prolonged and intensive workouts may decrease due to limited glycogen stores.
However, some studies demonstrate adaptation to this type of diet and the maintenance of athletic performance after an adaptation period.
