I've been commuting/riding every day for the past two years (20km round trip plus incidental trips to shops etc each day). I wasnt all that heavy to start with, but I dropped over 10 kg (22 pound) in the first few months. I had to buy new clothes as everything swam on me. I am now 67kg (148 pound) and 180cm (6 foot) tall. I havent been this fit since I was 12.