build muscle mass
The fastest way to build body mass is through weight training. To build muscle mass means you have to have a regular routine program targeting a specific group of body parts. For instance, if you want to build mass on your chest, a simple bench press on a flat back support can do the trick. In the absence of free weights, you can do push ups instead.
On the other hand, if you want to build muscles in the leg area, lunges can very effective too. Mass building requires heavy weight with less repetition. Military press in combination with other upper body exercises is also a good way to building up body mass. When performing all these exercises, remember to have a heavy protein diet as protein is the fundamental building block for cell and tissue regeneration.