Which one burns more fat

Exercising on an empty stomach lowers blood sugar levels, which can affect energy, focus, and cardiovascular stability. So even if fasted morning walks can enhance fat oxidation, they may not be safe or suitable for everyone.
​Studies suggest people prone to dizziness, lightheadedness, or fainting may experience low blood sugar during fasted exercise. Another study asserts that in fasted exercise, especially over 60–90 minutes, the body may start using amino acids from muscle protein for energy. Over time, repeated long-duration fasted workouts without proper nutrition can reduce muscle mass.
People with diabetes or hypoglycemia or those with heart or metabolic conditions should be more careful.