Layer · tolerate more carbs/hour
Gut-training plan generator
Your gut is trainable: with progressive exposure it absorbs more carbs per hour. Here's a live example plan — edit the inputs below and it rebuilds, with an honest check on whether your timeline is realistic.
Your gut-training plan
Your ramp
On trackfrom 30 g/h · 8 weeks · 24 sessions · DIY mix
Week 1 33–40 g/h
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33 g/h single carbLong / race-pace session — fuel at 33 g/h; train the gut, not recovery rides.
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37 g/h single carbLong / race-pace session — fuel at 37 g/h; train the gut, not recovery rides.
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40 g/h single carbLong / race-pace session — fuel at 40 g/h; train the gut, not recovery rides.
Week 2 43–50 g/h
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43 g/h single carbLong / race-pace session — fuel at 43 g/h; train the gut, not recovery rides.
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47 g/h single carbLong / race-pace session — fuel at 47 g/h; train the gut, not recovery rides.
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50 g/h single carbLong / race-pace session — fuel at 50 g/h; train the gut, not recovery rides.
Week 3 53–60 g/h
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53 g/h single carbLong / race-pace session — fuel at 53 g/h; train the gut, not recovery rides.
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57 g/h single carbLong / race-pace session — fuel at 57 g/h; train the gut, not recovery rides.
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60 g/h single carbLong / race-pace session — fuel at 60 g/h; train the gut, not recovery rides.
Week 4 63–70 g/h
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63 g/h 2:1 G:FPast the ~60 g/h single-carb ceiling — add fructose (≈2:1 glucose:fructose).
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67 g/h 2:1 G:FLong / race-pace session — fuel at 67 g/h; train the gut, not recovery rides.
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70 g/h 2:1 G:FLong / race-pace session — fuel at 70 g/h; train the gut, not recovery rides.
Week 5 73–80 g/h
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73 g/h 2:1 G:FLong / race-pace session — fuel at 73 g/h; train the gut, not recovery rides.
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77 g/h 2:1 G:FLong / race-pace session — fuel at 77 g/h; train the gut, not recovery rides.
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80 g/h 2:1 G:FLong / race-pace session — fuel at 80 g/h; train the gut, not recovery rides.
Week 6 83–90 g/h
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83 g/h 2:1 G:FLong / race-pace session — fuel at 83 g/h; train the gut, not recovery rides.
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87 g/h 2:1 G:FLong / race-pace session — fuel at 87 g/h; train the gut, not recovery rides.
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90 g/h 2:1 G:FGoal rate reached (90 g/h) — hold and consolidate.
Week 7 90 g/h taper
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×3 90 g/h 2:1 G:FTaper — rehearse your exact race intake (90 g/h). Don’t push a new max in race week.
Week 8 90 g/h taper
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×3 90 g/h 2:1 G:FTaper — rehearse your exact race intake (90 g/h). Don’t push a new max in race week.
Disclaimer — Educational tool, not medical advice. Gut training carries GI risk; build up gradually, rehearse in training, and back off if symptoms appear. Consult a sports dietitian for individual guidance.
How gut training works
The gut is trainable. Repeatedly taking carbohydrate during exercise upregulates intestinal transport and reduces the GI distress that caps most athletes' intake. In a controlled trial, two weeks of carbohydrate feeding during exercise cut gut discomfort by about 47% and carbohydrate malabsorption by 45–54%, and improved time-trial performance by 4.3–5.2% (Costa et al., 2017; Costa et al., 2023).
Past roughly 60 g/h, a single glucose-type carbohydrate saturates the SGLT1 transporter and oxidation plateaus. Adding fructose — absorbed by a separate GLUT5 route — lifts total absorption: about 2:1 glucose:fructose up to ~90 g/h, shifting toward 1:0.8 at 120 g/h (Jeukendrup, 2017; Hearris et al., 2022). On DIY plans, each session links the mixing calculator pre-filled for that dose and ratio.
No study quantifies an exact per-session ramp rate (Costa et al., 2023), so the 5–10 g/h progression is a practitioner heuristic, not a measured value. The feasibility check — not the curve — is what keeps the plan honest: it refuses timelines the evidence can't support.
Frequently asked
- How long does it take to train my gut to 90 g/h?
- Two weeks is the shortest studied block that produces meaningful gains; a larger jump (e.g. 30 → 90 g/h) sits more comfortably over 6–8 weeks. Spread the work across 2–3+ long sessions a week.
- Is 120 g/h better than 90 g/h?
- 90 g/h is the best-validated target. A 120-vs-90 g/h trial found higher oxidation but no performance or glycogen-sparing benefit, so the tool flags goals above 90 g/h as aggressive — useful for some athletes, not proven to help.
- DIY or branded fuel?
- Either works — the gut adapts to the carbohydrate, not the brand. DIY mixes cost a fraction as much; branded gels and drink mixes buy convenience and consistency. The plan links the calculator for DIY and suggests rate-matched products for branded.
- Should I do this in race week?
- No. The final 1–2 weeks rehearse your exact race intake at a rate you already tolerate. Never push a new maximum in race week — "nothing new on race day".
Citations
- Scheer V, Costa RJS, et al. 2023. "Gut-training for athletes" (systematic review). Sports Medicine. doi:10.1007/s40279-023-01841-0
- Costa RJS, et al. 2017. "Gut-training: the impact of two weeks of repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance." Applied Physiology, Nutrition, and Metabolism. PMID 28177715
- Jeukendrup AE. 2017. "Periodized nutrition for athletes" — carbohydrate transport, the ~60 g/h single-carb ceiling, and gut adaptation. Sports Medicine 47(S1), 51–63. doi:10.1007/s40279-017-0690-6
- Hearris MA, et al. 2022. Exogenous carbohydrate oxidation and the rate-dependent glucose:fructose ratio (1:0.8 at 120 g/h). European Journal of Applied Physiology. doi:10.1007/s00421-022-05019-w
Full evidence notes, confidence tiers, and the two findings this tool deliberately contradicts in the strategy brief are documented in the project's research dossier.