No simple way exists to burn fat and gain muscle. To accomplish this goal, you must be willing to commit to a lifestyle that supports exercises and other practices that help you burn fat and gain muscle by default. While weight training can help you build muscle, it won't necessarily help you burn fat. Riding an exercise bike can help you burn fat, but it may not be the best way to gain muscle. Generally speaking, the best way to burn fat and gain muscle is to develop a healthy routine of exercise and eating right that you can stick to long-term. No short-term, six-to-eight week program will help you if you do not commit to a new lifestyle.
Your plan to burn fat and gain muscle will revolve around exercise, of course. Lifting weights can help build muscle, as can plyometrics workouts and other physical activities such as hiking or biking. To burn fat, a cardiovascular workout is necessary; riding a bicycle, running, playing racket sports, or other activities that raise the heart rate and sustain it will help you burn fat. Such exercises must be combined with a healthy diet and the proper amount of sleep to be effective, and excess stress is a surefire way to counteract any gains made through working out.
The key to getting to a point in which your body can routinely burn fat and gain muscle is training the body to work harder. Muscles get built after repetition, and the body remembers how to do the exercises naturally. Starting small and working your way up to larger weights is a good idea, as the smaller weights get the body used to the lifting motion, and as muscle builds, greater weights can be lifted, building even more muscle. The same strategy works for cardiovascular workouts; starting slower or with shorter durations gets the body used to the strain. As you become more fit, you can do ladder workouts or interval training, which can both help you burn fat and gain muscle.
Consistency is key. You must commit to working out regularly and eating healthy foods daily. You will find that the more you work out and eat healthy, the more energy you will have to keep the routine going. The body can lose fitness, gain fat, and lose muscle mass relatively quickly, so maintaining a regular workout routine is essential. The path to burning fat and gaining muscle is less a matter of figuring out a workout routine and more a matter of changing your lifestyle.