What is the fastes and most effective way to lose belly fat?

Spot fat loss does . Not occur naturally. By losing weight in general some will probably be abdominal fat. But, we don't get to choose what area of body fat is lost from. Eat healthy ; be physically active. Calories burned must > those consumed. Tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge ; “bicycling” exercise on back. Do regular aerobic exercise.
Diet/exercise. Exercise your abdominal muscles. You lose fat by losing weight (3500 calories to the pound) but it is difficult to tell your body when to pull the fat from. Abdominal exercise can improve the muscles in your abdomen below the fat, and improve your physique. If you are overweight, you often are Insulin resistant, and the weight is stored in your abdomen. Otherwise liposuction will help.