Fasted training doesn't 'burn' your muscle
The idea that training on an empty stomach triggers muscle breakdown for energy is based on a real process — gluconeogenesis, the body synthesizing glucose from non-carb sources, including amino acids. The problem is this idea gets oversimplified into 'skip breakfast, lose muscle,' when the real scale of the process is much smaller.
The body's first choice for gluconeogenesis is amino acids from the circulating pool and liver glycogen reserves, not actively breaking down muscle fibers after just a few hours without food. Meaningful use of muscle protein for energy only kicks in after a much longer, deeper deficit — many hours of serious fasting combined with depleted glycogen stores, not a morning workout before breakfast.
A bigger factor in preserving muscle is your total daily protein intake and doing strength training that signals the body to hold onto muscle — not the specific hour of your last meal before a workout.