Moving onto the training. Anabolic Stretching A lot of beginner bodybuilders or people who are looking to add mass will tell you that 80% of gaining muscle is down to diet. This is absolutely rubbish. If you don't train properly then no matter what you eat you'll never gain any lean body weight. However, if you train progressively and don't eat very clean, then you can still gain muscle. Don't underestimate how important the training is!
The most important thing you need to consider when you're training is that the body will only react to the stimulus that it is put under. It will not grow bigger if you lift the same weights week in and week out. You must have PROGRESSIVE microtrauma in the muscle. This is absolutely fundamental.
To achieve this, start off with your weights at around 80% of your max, and add 5lbs to them each week. The momentum will take you past your old maximum and you'll keep adding the weight until you plateau. At which point either take a week off or deload so that you only lift 80% of your new maximum. Using this method for beginners is so powerful - I've seen people whack on over 3 stone of muscle mass in 6 months - they literally changed shape.