A better way to lean up and stay in good cardiovascular shape IMO is HIIT cardio. It is much shorter, and the results are quite impressive. Compare a mile runner to a 100 meter sprinter. Who is closer to a BBer physique? A 100 meter sprinter. Look at a guy like Maurice Greene. He is shredded, and has deep cuts and striations in his quads, whereas a 1 miler has cuts, albeit on a 20 inch quad. HIIT cardio may actually burn less calories while performing it, but that isnt the point. It is just like weight training. It raises your RMR quite substantially for 36 hours. There is no need to do it in a fasted state for optimal results. You should actually treat it like weight training, have a PWO shake with carbs and protein afterwards. I suggest starting off light. Do something like 10 100 meter sprints. Sprint 100 meters, walk 100 meters. Repeat for a total of 10 times. You can see nice results off this in only 2-3 weekly sessions. Once your conditioning is better, you can do things like 5 200 meter sprints, or 3 400 meter sprints, just make sure the rest period in between is at least double the sprinting time.