Interval Training

I had read from several websites, that one of the faster ways to reduce belly fat (and weight) is to do interval training. Interval training burns off more calories in lesser time.  Interval training is alternating bursts of intense activity with intervals of lighter activity. 
 
For example, walking. If you're in good shape, you could incorporate short bursts of jogging into your regular brisk walks. If you're less fit, you could alternate leisurely walking with periods of faster walking. There are several benefits that come from interval training, besides weight loss: increased insulin sensitivity and glucose tolerance, both of which are important for overall good health. Heart rate also improves.

For a further read on Interval Training.