Riding worked pretty well for me to lose weight. I lost 35 lbs and got much fitter at the same time. Of course eating better (and less if it's appropriate) will help too.
I don't like counting calories- if you eat real food that you make yourself, rather than packaged prepared food, it get very tedious to count calories. Real food is healthier and tastes better. When I want to lose weight I just cut back on food, making sure that I eat enough at the right time to support my riding. One other benefit of doing it this way is that you don't need to accurately count the calories burned while riding.