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Calculator · Fueling

Intra-workout fueling.

Carbs per hour · food equivalents · DIY mix

How many grams of carbohydrate do you need during a 90-minute ride, a 4-hour Ironman, or a Sunday long run? Drop your duration in, pick a target intensity, see your hourly target translated into the foods (and DIY ratios) you actually carry.

Use the calculator ↓ How it works

Plug in your session

The hourly target scales with duration, longer sessions need more carbs/hour as your liver glycogen empties. Pick Recommended if you don’t have a fueling history; Maximum only if you’ve practiced high-rate fueling and have a trained gut.

Your fueling target

Carbs per hour —
Total for the session —
Carry one (or mix)
  • — energy gels (25 g each)
  • — medium bananas (28 g each)
  • — Medjool dates (16 g each)
  • — g cane sugar
  • — ml sports drink (~6.5% CHO · — oz)
  • — rice cakes (20 g each)
DIY mix, Ideal ratio (Malto : Fructose 1.8 : 1): —
DIY mix, Simple ratio (1 : 1): —
Important notes
  • Concentrations > 8% may cause GI distress and slow gastric emptying.
  • 14–18% solutions aren’t optimal for hydration but can deliver carbs fast when chased with water.
  • Past ~60 g/h from a single source can trigger GI distress, combine glucose + fructose to push higher rates.
  • Hydration and electrolytes materially improve carb absorption. Don’t fuel dry.

How the targets are built

Three modes, three philosophies, pick the one that matches your training history and goal.

01

Minimum, the floor

Conservative rates: 0–75 g/h depending on duration. Best for athletes new to fueling, sessions in heat, or anyone with a sensitive gut. Won’t maximize performance, but protects the day.

02

Recommended, default

Most athletes, most sessions. 10 g/h on short stuff, ramps to ~90 g/h on Ironman-length efforts. Aligns with current sports-nutrition consensus (ACSM, Burke et al.).

03

Maximum, race rate

120–150 g/h on the longest events. Only if you’ve trained your gut, weeks of progressive fueling sessions, mixed glucose+fructose source, practiced at race intensity. Don’t debut on race day.

The food-equivalent breakdowns assume average sizes, check your actual gel and drink labels (they vary 20–35 g/serving). The 1.8 : 1 maltodextrin to fructose ratio is the multi-transporter sweet spot for absorption rates above 60 g/h.

Coach note

Your gut is a trainable organ.

The single biggest reason athletes blow up at hour 3 of a 70.3 isn’t legs, it’s a stomach that hasn’t been trained to process 80–100 g/h. SGLT1 (glucose) and GLUT5 (fructose) transporters upregulate with repeated exposure. Translation: practice your race fueling in training, not race week.

A simple build:

  • Weeks 1–2: 40–50 g/h on long rides, comfortable, build the habit
  • Weeks 3–5: 60–70 g/h, introduce mixed glucose+fructose source
  • Weeks 6+: 80–100+ g/h, dial in your specific products at race intensity

For the next layer, what your fat-burn rate is, where the carb crossover happens, how much fat oxidation you can rely on at race intensity, that’s the metabolic profiling test at the lab.

Metabolic profiling Coaching

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Want to know your actual fat / carb crossover?

The fueling target above is a population guide. Metabolic profiling at Yousuli measures your fat-oxidation curve and identifies the intensity where carbs become the dominant fuel, so you fuel for the watts you’re actually riding.

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