When high school science teacher turned elite ultrarunner Courtney Dauwalter first started running 50- and 100-milers in the mountains back in 2011, her approach to fueling resembled her previous gig: lots of experiments. For years, she tested out whatever food she found at aid station tables or items she saw other people eating, seeing how it would settle while she ran the course. “When I would arrive at an aid station, I would just copy the person in front of me, exactly what they would eat,” she tells Runner’s World . “If they were grabbing pickles and Doritos, then that’s what I was having. Or if they were drinking Coca-Cola and a handful of gummy bears, that’s what I would try. I really had no idea what I was doing for fueling ever.” Dauwalter’s “follow-the-leader” method lasted about six years before she realized something had to change. The turning point happened sometime around 2017, when she was racing a 50-miler and orbiting the same competitor for hours.…