Maximizing weight loss on ARC trainer

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I have been trying to get more physically fit. I do spin class 3 to 5 times a week, and have been for the last several months, but was looking for an alternative cardio routine for when I can't make spin class or on alternate days. I do resistance training as well. I started using the Arc Trainer's Weight Loss setting, speed bump, at Level 5 for 60 mins. It says that I burn 1000 cals. I am not concerned whether its more or less than stated as I know I am giving it a good work out. I do the machine intensely. Someone recently told me that I may be doing it too intensely for weight loss. I am curious at what would be the most effective time period/settings to acheive weight loss. I feel much better than I did in general. But I am not seeing any significant weight loss despite watching my diet. The person I talked to indicated that I could lose more weight if I actually reduce the time spend on the machine by 1/2. This is confusing to me. Any suggestions would be appreciated. Thanks.