Why your body needs glycogen.
What you eat, how often you eat, and your activity level all affect how the body stores and uses glycogen. Low-carb and ketogenic diets, as well as intense exercise, deplete glycogen stores, forcing the body to burn fat for energy.Glycogen production and storage
Most of the carbohydrates we eat are converted into glucose, our main source of energy. When the body does not need fuel, glucose molecules are combined into chains of eight to 12 glucose units, which form a glycogen molecule.
The main trigger of this process is insulin:
· When you eat food containing carbohydrates, your blood glucose level rises in response.
* An elevated glucose level signals the pancreas to produce insulin, a hormone that helps the body take glucose from the blood for energy.
* Insulin causes liver cells to produce an enzyme called glycogen synthase, which binds glucose chains together.
· As long as glucose and insulin remain in abundance, glycogen molecules can be delivered to the liver, muscles and even fat cells for storage.
Glycogen makes up about 6% of the total weight of the liver. The muscles accumulate much less (only from 1% to 2%), so we quickly run out of energy during strenuous exercises.
The amount of glycogen stored in these cells can vary depending on how active you are, how much energy you burn at rest and on the type of food you eat. The glycogen stored in the muscles is mainly used by the muscles themselves, while the glycogen stored in the liver is distributed throughout the body-mainly to the brain and spinal cord.
Glycogen should not be confused with the hormone glucagon, which is also important for carbohydrate metabolism and blood glucose control.
How your Body Uses Glycogen
At any given time, your blood contains about 4 grams of glucose. When the level begins to decrease-either because you haven't eaten, or because you burn glucose during exercise-the level of insulin also drops.
When this happens, the enzyme glycogen phosphorylase begins to break down glycogen to provide the body with glucose. Over the next 8-12 hours, glucose obtained from liver glycogen becomes the main source of energy for the body.
Your brain consumes more than half of the glucose in your blood during periods of inactivity. During a typical day, your brain's need for glucose is about 20% of your body's energy needs.
Glycogen and diet
What you eat and how much you move also affects the production of glycogen. The consequences are especially acute if you follow a low-carb diet, when the main source of glucose synthesis - carbohydrates-is suddenly limited.
Physical and mental fatigue
When you first switch to a low-carb diet, your body's glycogen reserves can be severely depleted, and you may experience symptoms such as fatigue and mental lethargy. As soon as your body adapts and begins to renew its glycogen stores, these symptoms should begin to disappear.
Water weight
In addition, any weight loss can have the same effect on glycogen stores. At first, there may be a sharp weight loss. After a while, your weight may stabilize and possibly even increase.
This is partly due to the composition of glycogen, which is mainly composed of water. In fact, the weight of water in these molecules is three to four times the weight of glucose itself. Thus, the rapid depletion of glycogen at the beginning of the diet causes water loss. Over time, the glycogen reserves are updated, and the water weight begins to return. When this happens, weight loss can stop or go to a plateau.
The positive results obtained at the beginning are associated with water loss, not fat loss, and are temporary. Fat loss can continue despite the short-term plateau effect.
Glycogen and exercise
The body can store about 2,000 calories of glucose in the form of glycogen. For endurance athletes who burn so many calories in a couple of hours, the amount of accumulated glucose can become an obstacle. When these athletes run out of glycogen, their performance almost immediately begins to deteriorate.
If you are engaged in strenuous physical exercises, there are several strategies that endurance athletes use to avoid a decrease in performance, which may be useful:
* Carbohydrate load: some athletes eat excessive amounts of carbohydrates before endurance competitions. Although the extra carbohydrates will provide enough fuel, this method has largely lost popularity, since it can also lead to excess water weight and digestive problems.
* Consumption of Glucose gels: Energy gels containing glycogen can be consumed before or as needed during endurance training to increase blood glucose levels.
* Follow a low-carb ketogenic diet: Following a diet high in fat and low in carbohydrates can lead your body into a ketoadaptation state. In this state, your body begins to access stored fat for energy and relies less on glucose as a fuel source.
