Personally if it's 'light conditioning' I'd go fasted of maybe after some BCAA. If under 30 mins fasted is OK in my opinion. All that 'fasted training will eat up all your muscle' bullshit should be put into context - 30 - 40 mins in the AM (if overall diet is in order) will improve conditioning and help drop some fat if done smart (German Volume Training would not be a good idea if you get my drift)
KB swings, skipping, shadow boxing, body weight circuits, brisk walking with a weighted vest. Much depends on your current condition, body weight and goals. Push -ups, pull ups and BW squats for time is a good one for example. Throw 100 rope jumps at the end of each round then hey presto.
I personally train 30-40 mins fasted every morning at 5.30.am (weights x 3 and conditioning x 3-4) and as my overall diet is spot on (pretty high carb/cal as I'm a Nak Muay Thai) the only thing burnt AM is glycogen and fat - I've noticed so lost in size or strength. I train 60-90 minutes MT in the evenings after work as well.
What's your current diet, weight, goals and condition?