Yes. Eating right is half the equation.I hit the gym 3-4 days a week but my diet's total shit. That is something that I need to work really hard on, and soon. If I ate better, I would feel better.
You don't need to eat free-range organic fair trade *insert label* food; just eat right means plenty fruits/veggies and meat/proteins and yes, enough carbs to sustain your efforts. That's it.
I feel the difference when I eat crappy food during a trip (you know eating at a restaurant almost all the time when travelling?).
And I feel the difference when I start eating at home again. I feel like I'm cleansing my system!