It's been about 11 years for me. I went from 475 down to about 175, and from using a cane to riding my bike nearly 10000 miles a year. I've gone into more details in other posts if you want to search back for them.
But basically nothing is the complete answer. I still have major, major eating issues. At this point I have absolutely no restriction on the amounts I can eat, so I have to maintain my weight the same way anybody else would -- and it's HARD. It was the right answer for me, or I'd have been dead now for many, many years. But be realistic and have a good support system.
There can be a bit much cheerleading going on, but check out obesityhelp.com for more information