Unhealthy lifestyle. It's a common contributor of our biggest health problems: stroke, heart disease, diabetes, cancer. What do the nation's top physicians recommend to keep your heart, mind, and body in optimally good health?

For the secrets to a long healthy life, WebMD turned to Richard A. Lange, MD, chief of cardiology at Johns Hopkins School of Medicine. His advice:

1. Daily exercise.
You brush your teeth every day; exercise is equally important for your daily routine. Turn off the TV or computer, and get at least 30 minutes of exercise every day.

To work your heart, it's got to be aerobic exercise. You've got lots of options: walking, jogging, biking, rowing machine, elliptical machine, swimming. But don't feel like you have to be an athlete. Walking is great exercise. Get 10 minutes here and there during the day. It all counts.

Start with something simple, like parking in the far corner of the parking lot -- so you get those extra steps to the door. Take the stairs one or two flights instead of the elevator. If you take public transportation, get off one stop early and walk the rest. Get out at lunch to walk. Or walk with your significant other or your spouse after work. You'll get a bonus -- relaxation and stress reduction.

2. Healthy diet.
Quit eating junk food and high-fat fast food. Your heart, brain, and overall health are harmed by foods high in saturated fats, salt, and cholesterol. There's no getting around it. You've got to replace them with healthy foods: lots of fruits, vegetables, fish, nuts, olive oil -- what we call the Mediterranean diet. Eat like an Italian, a Spaniard, a Greek! Enjoy!

3. Weight loss.
Too much body weight puts your health at great risk. When you take in more calories than you burn, you get fat -- it's that simple. You've got to eat less. You've got to exercise more. You've got to push yourself to make these lifestyle changes -- but you've got to do it to help avoid serious health problems like heart disease, diabetes, or stroke.