I disagree (sorry) AM cardio on an empty stomach 12 hrs after your last meal will do a hatchet job on BF because the body has no choice but to dip into those fat stores for fuel.after that the demand for nutrients are so elevated you will need a hi calorie /protein shake to supply the nutrients.
sure you can take a shake before cardio ,but! you are supply the body with fuel to burn and defeats the whole purpose of burning fat, it may raise your metabolism and burn some fat over a peroid of time but nothing like the latter.
RADAR