Human Performance Outliers Podcast with Zach Bitter Episode 476: Carbohydrate Fueling Strategies For Runners | Claire Shorenstein
Feb 20, 2026
Claire Shorenstein, a Board-Certified Sports Dietitian who helps endurance athletes with gut training and carb fueling, breaks down sustainable high-carb strategies. She explains how daily carbs change gut transporters, how to progress intake, practical during-run targets, and why hydration and sodium matter. Short, sensible steps for training the gut and scaling fueling to training load.
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From Marathon GI Disaster To Trained Gut
- Claire described her first marathon as a GI disaster that traumatized her into avoiding fueling.
- She overcame it by training her stomach and improving daily energy intake, eliminating those issues.
Fix Daytime Nutrition Gaps
- Plan three meals and multiple snacks so you don't go 2–4+ hours without eating during heavy training phases.
- Carry convenient carb-rich snacks and identify logistical barriers to daytime fueling.
Energy Availability Is A Body Budget
- Low energy availability is chronic stress that impairs many systems beyond performance.
- Think of energy like a budget: exercise costs reduce available energy for essential body functions.