If I were to give you 10lbs of clay and ask you to make me a pot, what is the heaviest pot you could make? 10lbs right? If I wanted a 15lb clay pot, I would have to give you more clay correct?
Body weight is the same way. Muscle are naturally going to weigh more when they get bigger. And in order to get bigger they are going to have to have a surplus amount of calories coming in for recovery and growth.
Unfortunately, many people hear the saying "increase your calories to grow" and it translates into "eat junk food and empty calories from fast food". Which will cause you to grow. Around the midsection. Increasing the calories is most important but try to make sure you are doing so in a way that most of them are coming from good clean sources. Avoid heavily processed foods or greasy (fried) items. While you can't completely eliminate them from your diet, try to limit them to the least amount that you can possibly get away with.
This doesn't mean eat boring stale foods. Good clean food can often be a treat in itself. One of my favorite things to eat as a "cheat meal" (fooling my taste buds basically) is a big homemade protein bar from NeedToBuildMuscle and a glass of low fat chocolate milk. I honestly consider that the perfect way to add clean bulking calories to your diet.
4 meals per day of good solid food (clean protein sources, leafy greens) + 3 of the NTBM protein bars and low fat chocolate milk cheats in between the breakfast and lunch meals, prior to workout, and after dark and you will see good improvement in a few weeks.
Stay off the scale, it is a fool's guide. You can gain weight very rapidly by putting on body fat, which takes twice the time and effort to get off once you have it. So don't be obsessed with trying to push the scale numbers up as fast as possible. Slow and steady will get you there in much better shape.
