I think fasted training works well for aerobic and sub threshold training but you need glycogen for the anything above! it all depends on your goals. If it's about losing weight i'd bag the VO2 work.... if you want to get stronger on the bike fuel for the VO2s and knock them out of the park.
thanks! Yeah, right now I am still focused on losing weight and not losing power. I figure once I lose some more weight I can start loading up on glycogen and then start hitting the VO2 workouts hard and hopefully increase the power at that point.