Normally when carbohydrates are eaten and digested, blood glucose rises. This causes insulin to be secreted from the pancreas. The insulin is needed for glucose to move into cells.
When insulin responds to a higher blood glucose, the glucose enters the cells where it is either used as energy, stored as glycogen, or converted for long-term storage as adipose (body fat).
Remember, diabetes is the medical word used when someone either doesn't have any insulin or when the insulin they have isn't effective. When someone doesn't have any insulin, it is called Type 1 diabetes. When the insulin is not effective, it is called Type 2 diabetes. In both cases, the blood glucose stays high unless medication is given or the diet is changed.