Diabetes has become a global epidemic, fueled largely by rising rates of obesity. The estimated number of people with diabetes has soared from 30 million in 1985 to 246 million in 2007, the International Diabetes Federation reports. Seven percent of Americans are diabetic, and a whopping one-third of Americans born in 2000 will develop the disease, the Centers for Disease Control and Prevention warns.

Anyone can become diabetic, and many who are don't know it. "In recent years there's a 50-50 chance that someone has one or more complications of diabetes before being diagnosed," says Dr. Richard Hellman, president of the American Association of Clinical Endocrinologists. Possible complications include damage to the heart, eyes, kidneys, nerves or feet.

The good news: Diabetes can often be prevented with weight loss, exercise and a sensible diet. A simple test can catch the disease early. Symptoms vary and aren't always present, but there are warning signs you can watch for. This is your guide to spotting red-flag symptoms that may indicate you're at risk.