Fasted Cardio and Heavy Weight Training

So I have been reading up on "fasted cardio". My normal routine had become about 100min of heavy weight/circuit training, followed by about 15-20min of cardio (elliptical, treadmill, bike, stair climber, etc.). I was quite successful, however, I decided to bump it up a little and went to 60 min of heavy weight training and 60 min of fasted cardio. I am at the gym at 5AM each morning so this routine isn't too difficult for me. I have only be on this new routine for about 8 days so I'm not sure of the "results". Anyone know how this works or if it even works at all? My goal is to shed body fat, while maintaining (and even adding) muscle. I currently (and for some time now) eat at a calorie deficit so weight gain is not my concern. Just do not want to lose what muscle I have built.

Any success, suggestions, etc...please send them my way.

Thanks.