Fueling for a long ride or fun w/ diet restrictions
I am on a low glycemic, gluten free, low or no dairy diet at the moment. (God, I sound so high maintenance!). It's working -- I feel a lot better, have rid myself of most of my GI issues, and have lost 15 pounds so far. Still about 30 pounds to go.
I wish I had thought to ask about this at my last appointment with the nutritionist, but I signed up at the last minute to do a 4 hour "spin a thon" to raise money at my local Y (it's next Saturday). I did 4 hours of spin last year, but I fueled with pretzels and gels. I never really got the whole fuellng while exercise thing to begin with, and now I am trying to do it while not messing up my diet too much.
So what should I eat, and when? I plan to have my normal meal replacement shake for breakfast (UltraMeal 360, for anyone familiar, per the doctor), but I know I can't go 4 hours on a spin bike with just that and water. Bring another shake? Something else? I fear gels will spike my blood sugar too much too fast, and now that I have been eating this way for a while, it will give me a raging headache.
I have the same issue for an upcoming half marathon as well - I know it will take me around 3 hours for that, and feel like I should have a fuel plan as a result. Help!