k-dog said:Long and slow seems to be the consensus...
buuuuuut, I was reading something recently about harder exercise for shorter periods and how it increases your metabolism - and keeps it that way for an hour or so. So the harder you work the faster it goes - for longer than you are doing the exercise.
So you can have your metabolism working really fast for a couple of hours after only a 45 min hard ride - which in the theory I read burns as much fat as riding for longer at a lower intensity.
HIIT (high intensity interval training) is supposedly the way to go but I've not tried it - sounds like it would be tough on a bike too - easier running.