Burning calories
According to my Diet and Exercise Assistant program for my Palm computer, I burn twice as many calories per minute on the bike as I do walking.
I love to walk, and walking has been my primary exercise for years now. Thanks to both walking an hour or so yesterday, and biking for more than 30 minutes, I burned off a considerable number of calories -- a total of about 725. That's 382 in 31 minutes of biking, and 343 in 55 minutes walking outdoors. (I don't count walking up and down stairs in the house.) If I could sustain that every day, I'd lose a kilo every 10 days, and 36.5 kg over the course of the year.