The High-Carb Revolution: How Today’s Champions Fuel to Win

Introduction

You’ve trained the legs, the lungs and the mind. But on race day, the limiter for many endurance athletes is still the gut. The “high-carb revolution” has changed how elites fuel marathons, Ironman, and Grand Tours: moving from 30–60 g of carbohydrate per hour to 90–120 g/h (and sometimes beyond) to sustain high power and pace. This isn’t hype — it’s physiology plus practice, and it underpins some of the fastest performances of the last decade. In this article, we’ll unpack the science behind high-carb fueling, show how world-class athletes are applying it, and explain how Carb Accelerator can support the approach by targeting the often-overlooked bottleneck: comfortable, efficient digestion.

The Problem 

Plenty of athletes still underfuel, either because they worry about gut issues or because they doubt they can absorb more than ~60 g/h. Meanwhile, professionals in running, triathlon, and cycling now routinely plan 90–120 g/h using “multiple transportable” carbohydrates (typically glucose plus fructose). The gap is twofold: understanding the physiological ceiling for carb oxidation, and developing a gut that tolerates higher intakes without gastrointestinal distress.

Science Deep Dive

Two key concepts explain the high-carb shift:

  1. Multiple transportable carbohydrate (MTC) delivery
    Glucose and fructose use different intestinal transporters (SGLT1 and GLUT5). Combining them increases total carbohydrate absorption and oxidation, reducing reliance on finite glycogen stores and delaying fatigue. Seminal work by Jeukendrup and colleagues synthesised this evidence and guided recommendations toward ~90 g/h for events ≥2.5 h. [1,2] 

  2. Raising the practical ceiling
    Recent studies and field data suggest elite athletes can oxidise large portions of very high intakes (up to ~120 g/h) when the gut is trained. Mountain-marathon research showed 120 g/h attenuated markers of exercise-induced muscle damage versus 60–90 g/h. [3] Stable-isotope work also indicates 120 g/h can drive higher exogenous oxidation compared with 60–90 g/h when delivered as drink, gels or chews. [4] Modelling of sub-2-hour marathon demands similarly points to very high exogenous carbohydrate requirements at those intensities. [5,6] 

Gut training is the bridge between theory and reality: repeated “feeding-challenges” in training reduce GI symptoms and may improve carbohydrate availability. [7–9] 

High-Profile Examples: Winning with High-Carb

  • Marathon running: Eliud Kipchoge’s historic 1:59:40 project showcased meticulous, high-carb fuelling via frequent carbohydrate feeds, widely reported in technical coverage of the INEOS 1:59 challenge. While not an official record race, it exemplified the performance ceiling unlocked by aggressive fueling. [10–11] 

  • Ironman / long-course triathlon: Contemporary pro race reports and analyses document Ironman champions adopting 90–120 g/h strategies, with some athletes targeting triple-digit intakes on the bike to protect the run. [12,13] 

  • Grand Tour cycling: WorldTour teams publicly discuss aiming for ~100–120 g/h during decisive stages, highlighting the role of gut training and careful product selection to hit targets day after day. [14] 

Importantly, observational work in triathlon also links higher in-race carbohydrate intake with faster finishing times, reinforcing the performance relevance outside the lab. [2,15] 

Practical Application

Step 1: Build your daily carbohydrate base.
For heavy endurance training, prioritise carbohydrate availability across the week; save “train-low” experiments for specific objectives, not race day. [16,17] 

Step 2: Progressively “train the gut.”
Over 2–4 weeks, rehearse race-intensity sessions with systematic increases in intake — e.g., 60 → 75 → 90 → 100–110 g/h — using glucose-fructose blends. This reduces GI symptoms and improves tolerance. [7–9] 

Step 3: Mix formats, match conditions.
Use a combination of drink mixes, gels and chews to distribute load across gastric emptying and intestinal uptake pathways; laboratory data show all can deliver high exogenous oxidation at 120 g/h when well tolerated. [4] 

Step 4: Calibrate to your output.
As a rule of thumb, riders often target carbohydrate kcal ≈ 40–50% of hourly work (kJ), which maps to ~50–125 g/h depending on intensity. [18] Start conservative, then step up with gut-training.

Step 5: Rehearse logistics.
Elite examples above weren’t one-off experiments; they were the end result of months of practice to nail frequency, textures, and timing under race stress. [10,14] 

How Carb Accelerator Helps

The high-carb revolution only works if your GI tract cooperates. Carb Accelerator is designed to support carbohydrate digestion and comfort during high-intake strategies:

  • Amylase helps break dietary starches into absorbable sugars, supporting the front-end of carbohydrate digestion under load.

  • Alpha-galactosidase targets gas-forming oligosaccharides; clinical studies show it can reduce gas production and related symptoms after high-FODMAP meals, which may aid comfort when fuelling frequently. [19–21] 

  • Ginger, peppermint, and fennel are traditionally used for GI comfort; peppermint/menthol can relax GI smooth muscle and ginger has evidence for reducing nausea in several settings. [22–25] 

These ingredients, alongside proteases and lipase to support mixed-meal digestion, are included in Carb Accelerator’s formulation, providing a science-led option for athletes progressing toward higher carbohydrate intakes.

Used alongside a structured gut-training plan, and your preferred glucose-fructose sports nutrition,  Carb Accelerator can be integrated before race-pace sessions and on key long runs/rides to support carbohydrate absorption, reduce GI distress risk, and enhance sustained energy during endurance training.

Conclusion

Elite endurance success increasingly rides on high-carb fueling plus a trained, tolerant gut. The physiology supports moving beyond 60 g/h when the event and intensity demand it, with growing evidence and elite practice around 90–120 g/h. Apply this progressively: build your carb base, train your gut, mix formats, and rehearse logistics. With its targeted digestive-support profile, Carb Accelerator offers a practical complement to help athletes participate in the high-carb revolution with greater comfort and confidence.

References

  1. Jeukendrup AE. The role of multiple transportable carbohydrates in endurance performance. Sports Med. 2010;40(4):275–292. PubMed

  2. Jeukendrup AE. Carbohydrate intake during exercise. Sports Med. 2014;44(Suppl 1):S25–S33. SpringerLink+1

  3. Viribay A, et al. Effects of 120 g/h carbohydrate during a mountain marathon on exercise-induced muscle damage in elite runners. Nutrients. 2020;12(5):1365. PMC

  4. Hearris MA, et al. 13C-glucose-fructose labelling reveals comparable exogenous oxidation from drink, gels, chews at 120 g/h. J Appl Physiol. 2022;133(3):676–689. Physiology Journals

  5. Lukasiewicz CJ, et al. Insights from modelling runners pursuing a sub-2-h marathon. J Appl Physiol. 2024;136(2):269–282. Physiology Journals

  6. Noakes TD. Are very high rates of exogenous carbohydrate ingestion required for a sub-2-h marathon? Front Nutr. 2025;12:1507572. Frontiers

  7. Martínez IG, et al. Effect of gut-training and feeding-challenge on GI status in response to endurance exercise: systematic review. Nutrients. 2023;15(9):2129. PMC

  8. Costa RJS, et al. Gut-training: two weeks of repetitive CHO challenges reduce exercise GI symptoms and improve performance. Appl Physiol Nutr Metab. 2017;42(5):547–557. Cdn Science Publishing

  9. Martínez IG, et al. Repetitive feeding-challenge with different nutritional formats improves GI tolerance and performance. Int J Sport Nutr Exerc Metab. 2025;35(3):173–184. Human Kinetics Journals

  10. WIRED. The science behind Eliud Kipchoge’s 1:59 marathon (nutrition highlighted). 2019. WIRED

  11. INEOS 1:59 diaries (Kipchoge on practising race-day nutrition). INEOS 1:59 CHALLENGE

  12. Triathlete. How Ironman World Championship pros use high-carb strategies. 2025. Triathlete

  13. Triathlete. Why Kristian Blummenfelt counts calories (fuelling insights). 2025. Triathlete

  14. EF Education-EasyPost. Tour de France: gut training and 90–120 g/h fuelling. 2025. efprocycling.com

  15. Pfeiffer B, et al. Nutritional intake and GI problems during competitive endurance events; higher CHO linked to faster Ironman finish times. Int J Sport Nutr Exerc Metab. 2012;22(1):1–11. PubMed

  16. Burke LM. Contemporary nutrition strategies for distance runners. Int J Sport Nutr Exerc Metab. 2019;29(2):117–129. Human Kinetics Journals

  17. Burke LM. Contemporary strategies to optimise training and performance. Int J Sport Nutr Exerc Metab. 2019;29(2):117–129. (overview). PubMed

  18. CTS/TrainRight. Mapping hourly work to carb targets (practical framework). 2025. Carmichael Training Systems

  19. Di Stefano M, et al. Oral α-galactosidase reduces gas after fermentable-carb meals. Eur J Gastroenterol Hepatol. 2007;19(8):689–693. PubMed

  20. Di Nardo G, et al. α-galactosidase improves gas-related symptoms in children. BMC Gastroenterol. 2013;13:142. SpringerLink

  21. Schiedermayer D. Is α-galactosidase effective for treating gas symptoms? Evid Based Pract. 2006. Lippincott Journals

  22. Chumpitazi BP, et al. Physiologic effects and safety of peppermint oil. Nutr Rev. 2018;76(11):761–773. PMC

  23. Best R. Mint and menthol: review of potential digestive benefits. 2022. ResearchGate

  24. Lien HC, et al. Ginger reduces vection-induced nausea and tachygastria. Am J Physiol Gastrointest Liver Physiol. 2003;284:G481–G489. PubMed

  25. Lete I, Allué J. The effectiveness of ginger in prevention of nausea/vomiting: review. Integr Med Insights. 2016;11:11–17. PMC

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