Which leads us to point number two: If you want to lose belly fat, you'll need to lose weight. If you stick to the following plan, you won't have to lose as much weight as you might think because your body will burn more fat for energy, but still. Reducing your body fat percentage will require losing some weight. Don't go into this thinking you won't have to lose weight, because that's the surest way to fail.
What does a HIIT workout look like? You could jog for two minutes, sprint for one minute, jog for two minutes, sprint for one minute. Or you could do a HIIT workout on a bike, or by running up stairs and then jogging back down. The key is that you go relatively all out for a short period of time, then recover by maintaining a moderate level of intensity, then go again.