Your Training Isn’t Broken—Your Fueling Is: RD Cortney Berling on Solving RED-S and Getting Faster

Most runners think their biggest limiter is training volume, paces, or genetics. Cortney Berling says it’s something much simpler: you’re not eating enough. Fresh off a 2:52:49 finish at the 2025 Eugene Marathon and armed with her credentials as a Registered Dietitian (MPH, RD, CDE), Cortney sits down to unpack RED-S (Relative Energy Deficiency in Sport): what it is, why it matters, and how to fix it before it derails your running and your health. Cortney’s perspective is unique because she’s lived it on every stage: from a 3,000m steeplechase PR of 11:05.95 at the University of Cincinnati, to a 1:22 half marathon in Portland (2024), to road wins like the Old Port Half in Maine (2017), to her current life as a sub-3 marathoner in Oregon. Along the way she’s been a board member and elite athlete coordinator with WMDP, coached high school runners, and led community seminars with OHSU Sports Medicine. She knows firsthand how under-fueling can lead to injuries, stalled progress, and experienced fertility challenges linked to under-fueling in her own journey — and how the right fueling strategy can flip the script. If you’ve ever bonked, felt flat despite training hard, or struggled to balance nutrition with performance, this episode is your wake-up call. Tap into the Cortney Berling Special. If you enjoy the podcast, please consider following us on Spotify and Apple Podcasts and giving us a five-star review! I would also appreciate it if you share it with your friend who you think will benefit from it. Comment the word “PODCAST” below and I’ll DM you a link to listen. If this episode blesses you, please share it with a friend! S H O W N O T E S -The Run Down By The Running Effect (our new newsletter!): https://tinyurl.com/mr36s9rs -BUY MERCH BEFORE IT’S GONE: https://shop.therunningeffect.run -Our Website: https://therunningeffect.run -THE PODCAST ON YOUTUBE: https://www.youtube.com/channel/UClLcLIDAqmJBTHeyWJx_wFQ -My Instagram: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠https://www.instagram.com/therunningeffect/?hl=en⁠⁠⁠⁠⁠⁠ -Take our podcast survey: https://tinyurl.com/3ua62ffz