There's a great story in this online newspaper link: http://www.startribune.com/lifestyle.../16782826.html
Scott Cutshall went from 501 lbs. on Thanksgiving of 2005 to 232 lbs. today. He did this mostly by biking and changing his eating. As a 38 year old father and husband, he was told by a doctor that he would be dead in 6 months without stomach reduction surgery. And in the condition he was in there was a 50% chance he wouldn't survive the surgery.
Instead of the surgery route he made a dramatic change in lifestyle and has lost 269 lbs. so far. Read the story to get the details. Very inspiring!