I definitely recommend getting some calories in before your workout. Im curious about why you're unable to eat before a workout. If it is early morning workouts, I definitely recommend at least a protein shake prior to lifting - or even a protein shake with some carbs WHILE you're lifting. If its not an early morning situation, you just don't like the feeling of working out after a meal - what if you eat and then give yourself plenty of time to digest? To answer your direct question, you can still gain muscle as long as your macros are calculated for muscle growth and you are putting in the workouts to make that happen.
