I had a patient bring a dozen Gatorades, a Tupperware of spaghetti, and two cans of Pringles to an overnight sleep study because sugars.  He said that the previous day his glucose was 1000 mg/dL (Holy shit) and that he feels faint if it drops below 300. FYI, all you not medical people, 300 mg/dL glucose is roughly the highest your blood sugar should ever be, and that's immediately following a meal, while your cells are taking up all that sugary goodness.