If you follow Chrisb1 's advice then I'll add that the fastest way to loose body fat is to exercise in the morning before consuming any calories as that is when your insulin level is at its lowest so you will be burning mostly fat, calories increase insulin levels and insulin is what tells the cells to store fat not burn fat! You should do moderate exercise so that you are not out of breath as the body needs oxygen to break down fat. Check out http://fitnessblackbook.com/
and HIIT