One of the biggest myths in the exercise world is that you can turn fat into muscle. Fat and muscle are two entirely different tissues. Fat is made up of triglycerides and muscle is made up of proteins. There is no mechanism to turn triglycerides into protein. Turning fat into muscle is a different way of saying, "I want to burn fat and build muscle."
Now that you know what turning fat into muscle really is, you can understand how to accomplish it. First, you will need to start burning the fat your body has stored by reducing your calorie intake and increasing your exercise.
You can figure out how many calories you burn by using the Calorie Calculator. To burn fat, you need to eat less than this so that your body can start using its fat stores for energy. Over time you will lose weight and your body fat percentage will decrease.
To build muscle you need to engage in resistance or strength training. Training your muscles involves pushing them farther than you did your previous work in order to overload and cause them to grow.