Hopefully you've eaten while on training rides so keep that as a good guideline. Label your wheels and check the wheel guidelines
eat a good bland breakfast (oatmeal, bagel, banana, etc) I put a bottle of water in my center pocket plus my mix in my cages since feed zones are a little dicey at times and gels. If you toss your extra bottle I always try to do it somewhere safe and that is close to some volunteers so I'm not just littering. I can only eat plain flavored gels so if you haven't trained with gels I'd suggest you keep the sweet flavors to a minimum until you know how your stomach reacts to the flavors.