I'm no MX'er, but I am a type 1 diabetic. I take two insulin shots per day and have for the past 6 years. I keep close watch over my sugar levels, and although my endurance level is not what it was before I'm still good for a long day of tough trail riding. Some things that I have learned are to eat right, have pasta or other grain based foods the night before a tough ride. This helps to keep your sugar from going too low. Carry some sort of gluecose with you in case you start to feel bad. I have a few tubes of gluecose tablets I keep in my hydration pack. If you start to feel bad then stop! I fortunately have never had any problems but if you start to feel faint or otherwise ill then stop and take a break, drink some fluids and take some gluecose if necessary. Water is the best fluid, but occasionally I'll drink some gatorade, just don't overdo it. Take your insulin as you normally would, but if you need to eat a snack before starting the race, having a slightly elevated sugar level for a SHORT period of time will cause no damage to you. Hope this helps.