Glad you got that figured out! It sounded like you were eating a lot of sugar on the ride, and that's what made me wonder if it might be the cluprit. I know that I can't eat a lot of those energy foods for that very reason.

Good experiment, and now you know!

SheFly

p.s.
A couple of women I know here will use baked potato or baked sweet potato as energy food on long rides. I know that one will use sweet potato, and make it a consistency that can be eaten from a ziploc-type bag. I have seen others pull potatoes from foil in their pockets. This might be a good alternative to the sugary energy products. I haven't tried it personally, though.