when considering what you're going to eat at any given meal, do you think in terms of performance? in other words, are you contemplating how what you ingest...and therefore digest...will affect your body, your brain, and your behavior? or are you typically too hungry to care, seeing food as a means to the end of your aching belly? how about your car? would you consider pouring, lets say, gatorade into your gas tank? or Pepsi? (have you ever poured pop onto your car battery? it literally melts away corrosion! and people drink it...yuck). your car probably wouldn't get too far with anything in the fuel tank but, well, the fuel that's meant to be in there. and so it is with our bodies. you can survive only so long feeding the appetite based on what you feel like eating in the moment...ie 'i'm starving. there's a donut. done'.