The dietary fiber is of two types. One is soluble fiber and the other is insoluble fiber. The soluble fiber usually forma a gel like substance on mixing with liquids. The soluble fiber binds with the fatty acids that are intermediary products of the fat metabolism and hence the overall cholesterol level in blood comes down. This can help you in a couple of ways to lose belly fat. Primarily the fat levels getting deposited in muscles and tissues are lessened. Secondly, the risk of being affected by a heart disease comes down. So do include food items like oats, bran, peas, nuts, barley, etc, as they are rich in soluble fiber.