An estimated 25.8 million Americans - 8.3 percent of the population - have diabetes. Of these, 18.8 million have been diagnosed and an estimated 7 million remain unaware of their condition. In 2011, 79 million American adults had a condition called pre-diabetes. This occurs when the blood glucose level is higher than normal but not high enough to be termed diabetes. The good news is that a diabetes diagnosis is not inevitable. Studies have shown that people with pre-diabetes who lose weight and increase their physical activity can prevent or delay diabetes, and even bring their blood glucose levels back to normal.