Even now, when "biking season" starts back up and I get out there, I'll be on the bike 1.5 hours or so. Every day if I can stick to it. Not shockingly, I lose a fair bit of weight during that time. Even without trying to do sprints or anything.
I'm sure I cheated some days and did the bus. But most days the walk was easier, as I didn't have to worry about timing and such. It was a crazy time, as I had given up on the gym and all other ideas, but that year I just dropped the weight like crazy. All because my car broke and I didn't have the funds to fix it. :D
(Of course, part of the "its been years" is that this is way more effective in your late 20s than it is later in life. At least, I think it is? Seeing how much time I was devoting to this, maybe I should try again. :D )