How would reduce belly fat without diet?

Simple process= stable or increasing weight means your daily intake of calories is equal or more than you burn of in your activities of daily living. If you don't want to change your intake of calories, you must increase the calories you burn daily to lose weight. Exercise is one way to do so. It is difficult to lose weight just by exercising, which triggers appetite.

Agree with Dr. Ferguson. An alternative is to get liposuction or abdominoplasty where fat would be removed surgically. Better would be to go on a diet and exercise.