I don't think it's very important to wear a belt or not. How long you run is more important. Generally speaking, jogging is a good exercise to reduce fat, but at the speed of 6-8 km/h, you don't really burn fat until you keep exercising for 30 minutes, so running needs to last for more than half an hour. You might as well try skipping rope. Skipping rope 1 hour can burn at least 1300 calories, which is equivalent to jogging for 3 hours and dancing for 2 hours, which is super slimming.