After 60 minutes of continuous cardio, it becomes counter-productive. You would be better off doing an hour in the morning, then another hour of walking or some activity in the afternoon or evening. That way your metabolism is activated twice a day.
Too much exercise can wear you out over time, so you need to take a break. That's why it is advised that you take one day off a week, and a week off every 3-4 months.
Lifting is important also. While the cardio is melting the body fat, lifting is building the muscle underneath.
Do or don't do; there is no try (Yoda)