You may think you already know the signs of diabetes: You’re thirsty all the time, you feel exhausted 24/7 and/or you’re constantly running to the bathroom. Yet a surprising number of Americans–including young and seemingly healthy women–have abnormally high blood-sugar (glucose) levels but don’t know it. The signs can be so subtle–or altogether absent–that the problem goes undetected, yet it increases the risk for heart disease and other serious health problems. As more and more of us pack on extra pounds, the incidence of diabetes and its recently defined precursor, pre-diabetes, is soaring in the United States. In fact, new research from the Centers for Disease Control and Prevention suggests that more than one in three girls born in the year 2000 will develop diabetes during their lifetime.

Approximately 18 million Americans have diabetes, either type 1–in which the pancreas doesn’t produce enough insulin (a hormone that helps regulate blood sugar)–or type 2, a far more common condition that develops over time in which the body cannot use insulin effectively to maintain normal blood-sugar levels. Unfortunately, about 5 million of these diabetics are unaware they have the condition, according to the American Diabetes Association (ADA).

What’s even more worrisome is that more than 24 million additional Americans have pre-diabetes, in which a person’s blood-sugar levels are higher than normal, but not quite high enough to be classified as diabetic. Research has found that the majority of people with pre-diabetes develop type 2 diabetes within 10 years, notes Francine Kaufman, M.D., immediate past president of the ADA and an endocrinologist at Childrens Hospital Los Angeles. More alarming, pre-diabetes, by itself, carries a 50 percent increased risk of cardiovascular disease. Yet, because it doesn’t cause symptoms, most people who have it are blissfully unaware of the danger.

Six simple steps

The good news is that there is a lot you can do now to lower your risk of developing both pre-diabetes and type 2 diabetes. The latest research suggests that more than half of new cases of diabetes could be prevented through lifestyle changes. Here are six steps that can greatly reduce your odds.