GLYCOGEN AND GLUCOSE
Glycogen and Glucose are the two forms of sugar that your body employs to store and use as energy . Glucose is the sugar your body converts into energy. Glycogen is the sugar your body stores in both your liver and muscle cells. Your body can't use glycogen directly as a source of energy, and cannot store glucose.
When you eat a well-balanced meal with both carbohydrates and protein, your body converts and absorbs the carbohydrates and part of the protein into glucose. It then attempts to maintain an even blood glucose level. When your blood glucose is too high, your pancreas produces insulin to convert some of that glucose into glycogen and then stores it for later use. When it is running low, it produces glucagon, a hormone secreted by the pancreas which stimulates your liver to convert some glycogen into glucose. Once converted, the glucose can be released into your blood stream. (The glycogen stored in your muscles can't be converted back into sugar, so it can only be used by your muscles.)
Your liver can only store 90 to 110 grams of glycogen (the equivalent of about three to four hours of normal activity). When your glycogen reserves are full, and you still have glucose in your blood or glucose being absorbed into your bloodstream from a meal, your liver then starts to convert glucose into fat. That is actually a normal process because with a regular size meal, you will invariably fill up your glycogen reserves. Therefore it is customary to store some fat when you eat. If you don't eat between meals, after around three hours your liver glycogen will be running low and your body will start converting that fat into energy until you eat your next meal. Overall, this is a healthy, natural process of filling up your glycogen supply, storing some fat, and then accessing that glycogen/fat reserve in between meals.