These tips from Glamour could help you undo some damage and make you feel better, starting today:

  • Let's say you pig out on junk food: Plowing through candy not only adds calories, it could put you at risk for heart disease. But you can undo the damage in just 3 days. According to Dr. Pamela Peek, if you resist your urge for sweets or processed food for just 72 hours, you'll suppress the hormones that cause your candy cravings.
  • If you're not exercising it can affect your metabolism, mood and even your risk for cancer. But you can undo the damage in a couple of weeks. Just do 20 minute short walks several times a week. Dr. Barry Franklin says that in 3 months your aerobic fitness can increase 10 to 20 percent, making you as fit as you were 5 to 10 years ago. And if that's too much to ask, just stand up. A Harvard study found that standing 2 hours a day reduced the risk of obesity and diabetes by 10 percent!
  • If you're still smoking: Every puff causes immediate damage. Within 10 seconds of inhaling smoke, carbon monoxide is absorbed by your lungs and goes straight to your heart, depriving your organs of oxygen. But you can undo the damage within minutes. After 20 minutes your blood pressure and pulse rate decrease almost to normal. Within 8 hours, carbon monoxide in your blood is replaced with healthy oxygen. Just 3 months after you quit, your lung function can improve 30 percent. And after 15 years, your risk of lung cancer and heart disease will be almost the same as a non-smoker's! How's that for mending your ways?!