Like many other ultrarunners, I suffer quite a bit from GI distress during very long efforts. Usually it hits me around mile 50 but it’s been known to strike as early as the first dozen miles.
Though I’m getting much closer to figuring this out, I’m always on the lookout for new information. That’s why I was totally stoked to find a really comprehensive article written by local Wasatch runner, Bruce Copeland. (I believe Bruce also puts on the Logan Peak 50K, which is a most excellent race that should be on everybody’s calendar.)
I found his work totally fascinating and extremely helpful. Go forth and read it here.