I know a faction of people on here will disagree with me on this, but try reducing carbs and increasing fat. Read some of Mark's old posts on the low carb flu. Reducing your dependency on carbs and training your body to burn fat should be your focus. Once you have done this then by all means, add in more carbs if you feel like it. I can eat huge amounts of sushi with white rice one day, then fast until dinner the next day without the low blood sugar symptoms you describe. The reason for this is when the carbs are burned off, my body is adapted to burn fat, whether it is dietary fat or stored body fat. If you are extremely lean this may be part of your issue, not enough stored fat to run off, but you could always supplement with dietary fat in absense of large quantities of carbs.