When you are trying to lose body fat fast the first step you need to do is figure you what your baseline calorie intake is.  Your baseline calorie intake is the amoune of calories you need to consume to maintain your current weight.  Knowing this is necessary due to the fact that how are you supposed to know how to adjust your diet if you dont know how many calories you take in to maintain your current weight.   Its silly to start or diet or fat loss plan if you dont know really where to begin.  There are mathematical formulas to figure out your baseline calorie intake, but the easiest way to do it is to do a search for calorie calculators on your favorite search engine. They will figure it out automatically for you.