Is it possible to make body to use already stored fat ? Cutting down food is not always easy , sometimes it is hard to control hunger ; if do so most of the time it tends me to have a large meal when get the next opportunity .
The best way to have the body use stored fat is to exercise.
However, there is a tip i often see, and that tip is fasted cardio.
This consists on doing some form of cardio early in the morning, after you wake up. The reason for this is, when you are sleeping your body will conserve its carb deposits and when you start your exercise before consuming anything the body will tend to burn mostly fat and potentially can consume your muscles as well as energy.
This is why BCAA's (supplements) are often recommended when you do fasted cardio, as it supresses your body from breaking down your muscles during workout.
Another "tip" is bodybuilding. As your muscles grow, they will start consuming more energy just to maintain them. What this means is, bigger muscles = more calories burned over the day. This is a long term tip thou :).
If you want your body to use already stored fat, the first thing you need to do is make it available by reducing your levels. You do this by minimizing your intake of carbohydrates and increasing your intake of protein and fat. The next thing that you need to do is increase your BMR. You do that by gaining lean body weight, the more lean body weight you have, the more calories you will burn. Most important, don't under eat just yet, conversely you may want to overeat slightly so your body can add the extra muscles that will help you burn that fat later on. Once you have increased your BMR by gaining some substantial muscle mass, switch to slightly under eating (while maintaining the low carbohydrate intake) and go from a muscle building program to a strength training program. Its better even than cardio for burning calories and its a good way to check if you are not under eating to much. A quick drop of strength is usually a sign that you are not consuming your fat but are consuming your precious muscular proteins.
Try searching info on Brown Fat. It's known now that brown fat can burn off calories, if stimulated. That's one reason why some lucky people (like me) can eat lots of food without getting fat. One way of stimulating brown fat is by getting cold. Don't get ill by being too cold, but try lowering the thermostat if you're inside, it can activate your brown fat to burn calories to keep you warm ..and you'll save money on the energy bill at the same time!