I find that there's way too much focus been used on one side of the coin instead of balancing out the equation. In English; too much focus on eating/calories and not enough on what effect exercising/frequency plays in this whole gaining/losing weight business. You grow on your days off; you grow when you're sitting watching TV, you grow when you're relaxing, you grow when you're not in the gym, you grow when you train just enough and no more, you grow when you understand that your extracurricular activities have to be taken into account and that too much of their inclusions even though is great for maintaining or even speeding your metabolism, could be one of your weakest link in this whole chain of aiming to supercompensate and moving forward.
Go ahead and eat a ton of calories, it would mean nothing unless you learn to slow down, allowing those calories to build you up instead of keeping your fast metabolism ticking over. Hit the iron hard; total body workout three times a week, and enjoy growth time during your four days of smart recovery. The more you train, as in the higher the frequency (irrespective of body part being trained), the faster your internal engine is going to be revving, it's that simple. If it was your V8 car doing it, you'd see a mechanic and ask him to reduce the revs slightly so as to not guzzle so much fuel whilst sitting at the light idling away, wouldn't you?! So why not the same with your own metabolism and its revving cycle? After 35 years of training, if I've learnt one thing about gaining or losing weight; it's the fact that you can not ignore the speed of your metabolism (or lack thereof), and hope your diet alone would take care of business. Focusing on one side of the coin won't cut it; only when you take into consideration your training frequency (and your extracurricular activities), coupled with what you're eating, would you then be able to determine where this magnificent ship will sail.