There's really no effective way to lose fat that quickly and retain all your muscle. you'll have to lose some muscle to shed fat that quickly. The only way I can see saving alot of muscle is with AS but I'm no expert on that topic so if somone else can chime in on that, feel free to. Any way, if you want to shed fat fast, start cutting carb, sugars, and fats drastically. Stay under 100gms of carbs on workout days and under 70 on sedentary days. Up your protien intake to 1.5gms per lb of body weight. Oh and eat 6 meals a day and drink about 2 gallons of water daily. HTH, and do cardio first thing in the mornings on an empty stomach.