your are not going to loose weight riding. weight loss will be through a careful eating plan off the bike. get professional help for such plan. Ride as often as you can building up base miles such as 10% per week with a back off recovery week every 4th week. One long ride a week. don't worry about speed. just ride and eat less but eat well. It takes time and commitment. no easy short cuts. after a year or two of this with base up and weight down you can do intervals once or twice a week.