Abdominal breathing is a core training method, which is aimed at core muscles rather than fat. Abdominal breathing is not what you understand.
Fat will not disappear. Scientifically speaking, fat is the storage form of energy, and energy cannot be generated and disappeared out of thin air. It can only be converted from one energy form to another, or from one substance to another, and the transfer of fat energy is from chemical reaction to mechanical energy for muscle exercise!
Therefore, to consume fat, there is only one way to exercise, and it is a scientific exercise.