Confession: I grew up in a house filled with carbs. Unhealthy carbs. I didn't even know what runners food was until I researched it while training for my first 5K. Runners food seemed like this mystical thing that only marathoners needed to know about. I can totally eat this cupcake before a run, right?! It has sugar. And sugar makes me energetic...which means it's fuel....right?! Wrong. Very wrong, self. Luckily, I learned that runners food isn't complicated. In fact, it's based on basic…