Personalized Endurance Fueling

Know exactly what to eat, every hour,  on race day.

Personalized, hour-by-hour fueling plans built from sports science — not guesswork. Adjusted for your body, your race, and your weather.

Build Your PlanFree. No account required.
9
Race types
Marathon to 100-miler
4
Nutrients tracked
Carbs, fluid, sodium, caffeine
5yr
Weather history
Location-specific averages
60s
To build a plan
Free, no account needed

Plans built for your race

Every distance has different fueling demands. We account for that.

Ironman 140.6140.6 miSwim/bike/run segment transitions
Ironman 70.370.3 miHigh-intensity tri fueling
Marathon26.2 miPrecision carb timing
Ultra 50K31.1 miBeyond-marathon gut strategy
Ultra 50 Mile50 miLong-effort real food plans
Ultra 100K62.1 miOvernight fueling windows
Ultra 100 Mile100 mi24hr+ sustained nutrition
Century Ride100 mi bikeOn-bike fueling cadence
Gran Fondo~80–120 miClimbing-adjusted effort

Racing a specific event? Browse 400+ races with historical weather data and race-specific fueling strategies.

How it works

Three steps. One blueprint.

01

Enter your race

Race type, target time, body weight, experience level. Takes about 60 seconds.

02

Get your blueprint

Hour-by-hour carb, fluid, and sodium targets — adjusted for race-day weather at your location.

03

Race with confidence

Save your plan, export to PDF. Tape it to your bike, screenshot it for your watch. Go race.

Your fueling blueprint

Everything you need, nothing you don't.

Each plan is tailored to your body weight, race distance, target time, experience level, and predicted weather conditions.

Hour-by-hour timeline

Not just totals — exact targets for every hour of your race, with ramp-up pacing built in.

Carb targeting

40–120 g/hr based on your experience level and gut tolerance, using glucose + fructose science.

Fluid + sodium

Sweat rate estimation tuned by temperature, humidity, and intensity. Sodium dosing to match.

Weather-adjusted

Auto-fetches forecast data for your race location. Plans adapt to heat, humidity, and rain risk.

Product suggestions

Specific recommendations — gels, chews, drink mix, or real food — mapped to each hour.

Risk flags

Warnings for high heat, gut fatigue in long races, and hyponatremia risk — before race day.

How it works

The numbers behind your race plan.

60–120 g/hr
Carbohydrate oxidation

Current sports science consensus for events over 2.5 hours, using dual-transport glucose + fructose pathways.

900–1000 mg/L
Avg. sodium in sweat

We estimate your losses and recommend 70–80% replacement — full replacement can cause more problems than it solves.

1.0–1.2 kcal/kg/km
Running energy cost

Remarkably consistent across paces. We use this to estimate your burn, then target 30–50% caloric replacement.

+0.1 L/hr per 5°F
Heat sweat adjustment

Sweat rate scales with temperature above 60°F. We model this alongside humidity to estimate your fluid needs.

Formulas based on Jeukendrup (2014), Sawka et al. (ACSM Position Stand), Gagge & Stolwijk sweat models, and current ISSN guidelines. All calculation logic is open and testable — no black boxes.

From the blog

Go deeper on the science.

Aug 30, 2026·18 min read

Ironman 140.6 Nutrition Plan: What to Eat During a Full Ironman

Build an Ironman 140.6 nutrition plan with carb targets, bike and run fueling, race-morning food, special-needs backups, and a worked 12-hour example.

Read: Ironman 140.6 Nutrition Plan
Aug 24, 2026·10 min read

What to Eat After a Marathon: A Practical Recovery Nutrition Plan

What to eat after a marathon when your stomach is done: practical carb, protein, fluid, and meal ideas for the first hour and the next two days after racing.

Read: What to Eat After a Marathon
Aug 17, 2026·11 min read

Running Is a Rotational Movement: What Your Spine, Pelvis, and Arms Actually Do

Running rotation biomechanics explained: how your arms, pelvis, and spine coordinate, what the science supports, and which drills may actually help your form.

Read: Running Is a Rotational Movement
Aug 2, 2026·16 min read

Isometric Exercises for Tendon Health: What Endurance Athletes Should Know

Isometric exercises for tendon health can build stiffness and capacity. Learn what holds can and cannot do, plus practical examples for endurance athletes.

Read: Isometric Exercises for Tendon Health
Jul 20, 2026·16 min read

100-Mile Ultramarathon Nutrition Plan: What to Eat, How Much, and When

Build a 100-mile ultramarathon nutrition plan with hourly carbs, real food, hydration, caffeine, crew timing, drop bags, and overnight fueling by hour.

Read: 100-Mile Ultramarathon Nutrition Plan
Jul 13, 2026·15 min read

Ironman Hydration Plan: Fluids, Sodium, and Bike Bottle Setup

Build an Ironman hydration plan with fluid and sodium targets, bike bottle math, aid-station timing, run-course cups, and practical hot-race backup plans.

Read: Ironman Hydration Plan
All posts →
Peer-reviewed foundations

Every formula traces back to Jeukendrup, Sawka et al., and ACSM position stands — not blog posts.

No black boxes

All calculation logic is transparent and unit-tested. You can see exactly how your plan is built.

Always free

No paywall, no account required, no “premium tier.” Build unlimited plans and export PDFs for free.

Stop guessing. Start fueling.

Your race nutrition plan takes 60 seconds to build. It's free, no account needed, and you'll walk away with an hour-by-hour blueprint you can actually use.

Build Your Fueling Plan