At my heaviest I was 322lbs but still reasonably active by virtue of not driving, I had to walk everywhere or catch the bus.
I've since lost 114lbs and have a little way to go to reach my goal weight of 196 or below.
I've done it on my own, sensible eating (although I still eat treats regularly and drink alcohol several times a month) walking, running, going to the gym ( I quit the gym and have have used my monthly gym fee to buy my custom road bike) and cycling.
I have watched TBL occasionally (manily the Aussie version) if only because the size of some of the contestants makes me feel fantastic about myself).
What strikes me is that even though the participants do huge amounts of high intensity excersise many don't seem to lose much more than I have and still do on some weeks on just moderate activity, everyone is different though I guess.

I haven't found losing weight and getting fit to be especially difficult, making the decision to begin down that path just took me quite a while. My main incentive was that I wanted to be sporty, I wanted to be one of those people whose main hobby is some kind of athletic activity as I had always admired those types of folks.

A few (not very good) pics of me over the past 24 moths or so,

2008

May this year, still wearing clothes a size too big though (shopping budget struggling to keep up with weight loss)
Have enjoyed having my hair cropped now that I have lost the weight from my face and neck.

July this year at a premiere of a friends movie (it was a long night lol and that's all I'm saying regarding my dishevelled appearance)