The grapefruit diet that Huge Tom has just posted would be an excellent way to lose stomach/any fat. After a few days depending on your current level of carb consumption you will soon see a noticeable decrease in bodyfat.

Just be sure to eat plenty if protein in the way of meat or fish to avoid body consuming its own store of essential amino acids (your muscles and other organs) and don't be afraid to eat fat. You need essential fatty acids as well as essential amino acids to function/live!