Achieve your goals or eat Alpo!
I've spent most of my life as a skinny bastard. It took more than two decades of lifting to get my body mass index up to a mirror-friendly 26.
The other day while standing in the checkout line at the local supermarket, I noticed a woman feverishly scratching one of those scratch-off lottery ticket thingies. I don't know what they're actually called, but I'm sure you've seen them.
The older and wiser you get, the more you start to realize there are certain "universalities" common to successful outcomes in all of life's endeavors. These realizations are as certain as the law of gravity, albeit less obvious. You should know and understand these common threads because they make success less random and more predictable.
Sit down with a bunch of bodybuilders and ask them to sum up all the important stuff they've learned and you'll probably hear some interesting info. But sit down with a bunch of experts in the field, guys with years of experience training themselves and working with others, and what you hear may change how you eat and train forever.