And just so you know your not alone, I've also had bouts of the loose stool but usually only 1-2 times a day (sounds like your's is more often ). The carb-up day shut that down for a few days though.
Sand still sounds worse, I can never control the bike when I hit a sand patch. I always have to get off and walk it.But this morning on my bike ride into work (all uphill, though I normally crank with ease) felt like pedaling through cream cheese frosting. No, not sand. Cream cheese frosting. Or maybe peanut butter. Yeah - like pedaling through peanut butter.