I have very similar goals (training for a half and full marathon this year). I'd say mix it up. I do a long run each week, each week adding a mile to the distance (this weekend I'm up to 10 miles). Keep in mind that every 3 weeks or so scale the long run back to give yourself a chance to recover. In addition I also do a speed workout once a week (i.e. hills, mile repeats, track workouts, etc), a tempo workout, and 2 - 3 easy runs. Intense running burns more calories per minute than slower running, but slower running burns more over the run since you are running for a much longer period. This is why you need to mix it up.Originally Posted by nal
Sorry, my main priority is weight lose. Endurance is a close second though.