I've always found it helpful to understand bio-mechanics making everything all fit together, here is an interesting vid on insulin and GLUT4. GLUT4 is particularly interesting for active people, moreover weight lifters because it's responsible for glycogen storage whether into muscle or adipose (fat) tissue. Let the following vid illustrate this.
Ill also talk a little on carbohydrate metabolism, which begins with digestion in the small intestine where monosaccharides are absorbed into the bloodstream. Blood sugar concentrations are controlled by three hormones: insulin, glucagon, and epinephrine. If the concentration of glucose in the blood is too high, insulin is secreted by the pancreas. Insulin stimulates the transfer of glucose into the cells, especially in the liver and muscles, although other organs are also able to metabolize glucose.
In the liver and muscles, most of the glucose is changed into glycogen by the process of glycogenesis (anabolism). Glycogen is stored in the liver and muscles until needed at some later time when glucose levels are low. If blood glucose levels are low, then eqinephrine and glucogon hormones are secreted to stimulate the conversion of glycogen to glucose...
