There are many, better ways to get healthy and fit, than running (No, don't take your training advice from The Biggest Loser, cringe). If you do enjoy running or it is part of your sport or occupation, understand that it is a stressor on the body, and more is not better. Extensive running, especially without resistance training has several adverse effects on the body (decreased muscle mass, bone density, HDL, etc.).
Want more evidence against pounding the pavement (for your health), Art Devany had a great post on his blog: The Top Ten Reasons Not To Run A Marathon (http://www.arthurdevany.com/?p=1449)