Nice run, Susan!

Usually an upset stomach after running or cycling for me means that I ate the wrong thing - before I started or while exercising. It feels like gas is compressed in my stomach and anything I eat goes on top of it, and I feel nauseous. Until the gas leaves my system, I don't want to eat. Usually takes a couple of hours after I finish exercising before I stop feeling nauseous and can eat again. I'll also get it if I eat the wrong thing while exercising at a higher heart rate - low rates and I can eat anything, but up into the right zone for me and the wrong food is trouble. I, too, have to stick to hammer gels, I can also tolerate accelerade.

I've had it with higher fiber cereals/foods before exercise, candy bars (like a fun size snickers) before/during exercise, and gu chomps/clif shot bloks by themselves (if I alternate chomps/gels it's better, but something about the chomps at higher heart rates just gets my gut). There's definitely an exercise timeline factor, too, if I exercise for 90 minutes to 2 hours I can tolerate a lot more than 2-3 hours and up.