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120 g of carbohydrate per hour in endurance: trend, limits and personalization

By Tomás Leal · Sports dietitian12 min readPublished 09/14/2026
Sources
5
Validated claims
3
Dominant evidence
Limited
Freshness
09/14/2026
120 g of carbohydrate per hour in endurance: trend, limits and personalization
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In brief The 120 g of carbohydrate per hour figure is increasingly visible in endurance sport. It is a possibility studied in trained athletes, not a universal target. The useful question is what amount supports the work required in the real conditions of the event.

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1. Why 120 g/h is trending Traditional guidance commonly used 30–60 g/h, rising to about 90 g/h for efforts longer than two and a half hours. Recent 2026 reviews discuss athletes experimenting with 100–120 g/h. The *Sports Medicine* review says some athletes can tolerate ultra-high intakes, but performance benefits above 90 g/h remain insufficiently established. The *Journal of Nutrition* review considers 120 g/h potentially accessible to trained participants while rejecting a universal recommendation. This is an emerging research and practice trend, not an exact Google Trends measurement.

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2. What it may change Glucose and maltodextrin mainly use SGLT1. Fructose uses GLUT5, so a glucose–fructose blend can increase exogenous carbohydrate oxidation above the usual single-source ceiling. Ingestion, absorption and oxidation are different: unoxidized carbohydrate may remain in the gut and contribute to fullness, nausea, bloating or diarrhea.

A 2020 mountain-marathon study compared 60, 90 and 120 g/h in elite runners after gut practice. The 120 g/h group had lower muscle-damage markers, but this was a specific protocol and biomarkers are not the same as a proven race-time improvement. A recent metabolic study in eight elite male marathoners found higher exogenous oxidation and better running economy at 120 g/h, alongside more pronounced gastrointestinal symptoms. The sample cannot represent all athletes.

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3. Limits of a universal number A 75-minute easy session, a three-hour marathon and a five-hour cycling stage do not require the same plan. A dose can be tolerated without being necessary. Running impact, heat, concentration, fluid access, stress and solid food all change gut response. Laboratory cycling cannot automatically predict a hot trail run.

Recent evidence is incomplete: many studies are short, use small samples, or include trained men. Data for women, beginners and very long real-world events remain limited.

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4. How to personalize fueling Start with duration and intensity. Below about one hour, fuel during exercise is often unnecessary when starting well fed. Between one and two and a half hours, 30–60 g/h is a common starting range when needed. Beyond two and a half to three hours, trained athletes may progress toward 60–90 g/h. Consider 120 only after those steps and only when the event and tolerance justify it.

StepTestObserve
1Record current intake and symptomsEnergy, hunger, nausea, stool, pace
2Repeat a comfortable doseTolerance in similar conditions
3Increase in small stepsDigestion and intensity
4Above 60 g/h, consider glucose + fructoseTaste, concentration, water
5Rehearse the target doseFinal race decision

Change one variable at a time. Count drinks, gels and food. Start early and spread intake. If symptoms appear, reduce the dose or intensity before assuming you need more gut training.

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5. Choose formats critically Drinks combine carbohydrate and fluid, but concentration and thirst matter. Gels are compact but concentrated and may need water. Chews and familiar foods add variety, though solids can be harder at high intensity. No hydrogel, ratio or package guarantees performance. Test the exact product and plan in training.

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6. Gut training Tolerance can improve with repeated practice over several weeks. Progress only when the previous dose is comfortable, and reproduce terrain, pace, temperature and drink format. On very long events, alternating liquid and solid or sweet and less-sweet options may be more realistic than forcing one formula.

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7. Race-day decision Ask: Is the effort long enough? Is intensity high enough? Have I tested this dose in the same sport? Can I drink appropriately? Is the plan practical and pleasant? If not, a lower dose is probably the better starting point.

09FAQ ### Is 120 g/h the new minimum? No. It is a studied or reported intake for some trained athletes, not a universal minimum.

01Must glucose and fructose always be combined? No. Combining them is mainly relevant when targeting high intakes.
02Why do I get gut symptoms at 120 g/h? Dose, concentration, fluid, heat, intensity, impact and lack of practice can all contribute.

Sources

Peer-reviewed studies and institutional references used for this article.

  1. 1Journal of Nutrition· 2026
    Systematic reviewLikely

    athlètes d’endurance, revue narrative contemporaine

    View source
  2. 2Sports Medicine· 2026
    Systematic reviewLimited

    athlètes d’endurance, revue des apports ultra-élevés

    View source
  3. 3Journal of Applied Physiology· 2026
    Randomized controlled trialLimited

    huit marathoniens masculins d’élite · 8 participants

    View source
  4. 4Nutrients· 2020
    Randomized controlled trialLimited

    coureurs d’élite, marathon de montagne · 21 participants

    View source
  5. 5International Journal of Sport Nutrition and Exercise Metabolism· 2011
    Official guidelineEstablished

    adultes pratiquant l’endurance

    View source

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By

Tomás Leal

Works with endurance athletes on periodised fuelling strategies.

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