Third season commuting (40 minutes each way). Lost about 10 lbs per season. Probably ate more and built muscle/lost fat. Went on a "pre diabetic" diet (ie: around 2000 cal per day, big breakfast, 3 meals with snacks in between...proper nutritious diet... balanced with carbs, protien, fat) in Jan and have lost 30 lbs... so guess it works best if you do both (at least for me). HAve started commuting again and find I have to eat more calories to avoid losing too much weight (who woulda thought?).