The exact cause of prediabetes is unknown, although researchers have discovered some genes that are related to insulin resistance. Excess fat — especially abdominal fat — and inactivity also seem to be important factors in the development of prediabetes.

What is clear is that people who have prediabetes aren't quite processing sugar (glucose) properly anymore. This causes sugar to build up in the bloodstream instead of doing its normal job of fueling the cells that make up muscles and other tissues.

Most of the glucose in your body comes from the foods you eat, specifically foods that contain carbohydrates. Any food that contains carbohydrates can affect your blood sugar levels, not just sweet foods.

During digestion, sugar enters your bloodstream and with the help of insulin is then absorbed into the body's cells to give them energy.

Insulin is a hormone that comes from the pancreas, a gland located just behind the stomach. When you eat, your pancreas secretes insulin into your bloodstream. As insulin circulates, it acts like a key that unlocks microscopic doors that allow sugar to enter your cells. Insulin lowers the amount of sugar in your bloodstream. As your blood sugar level drops, so does the secretion of insulin from your pancreas.

When you have prediabetes, this process begins to work improperly. Instead of fueling your cells, sugar builds up in your bloodstream. This occurs when your pancreas doesn't make enough insulin or your cells become resistant to the action of insulin or both.

Jan. 26, 2012