Your brain has 87 billion neurons and uses up 25 percent of your total energy and 50 percent of your body's oxygen, yet we rarely think about eating to "support" this vital organ. Though we often feel exhausted from doing nothing more than trying to focus for hours on end, it never occurs to us to fuel up our brains. Only when we experience "brain fog" or a lapse in concentration, productivity, creativity or sharpness, does it occur to us that our sluggish operating system may be in need of better fuel and a little maintenance care. Think of the last time you had an off day (couldn't find the right word, remember a name, get your project or tasks done). Chances are it coincides with a period of eating sugary junk food, sleeping poorly, or a day of not exercising and spent mostly in a chair or being sedentary.