NOTHING works fasted, if you are natural. Especially if you are dieting down.
If you are dieting down the only anabolic moment in your day is the training session. If you turn it into a catabolic event by not having any nutrients in you when you train, you WILL lose muscle mass.
Not having carbs pre-workout will drastically increase cortisol release which will make it pretty much impossible to avoid losing muscle mass while dieting down.
And the training brings blood to the muscle. If you have amino acids (from protein) in your blood when training you are thus sending the amino acids that will be needed to rebuild muscle directly where they will be needed. This is a golden opportunity to build muscle.
Doesn't have to be an actual meal. Can be a shake (like PLAZMA) but you need carbs and protein in you when you are training, especially if you are dieting down.
Sadly your body doesn't care about what is convenient.
The truth is that strength training (and even cardio) fasted in the morning is probably the worst thing you can do when it comes to building or at least keeping muscle. If you strength train fasted you might even LOSE muscle because of the workout.