Race Nutrition Calculator
BetaBuild a complete, evidence-based nutrition plan for your next cycling race. Get personalized carbohydrate, fluid, and electrolyte targets with a time-stamped fueling schedule.
Basic Information
Your body composition affects nutrition requirements
Performance Data
OptionalFTP helps calculate intensity-based nutrition needs
Improve Your Race Nutrition Knowledge
Dive deeper into the science behind race nutrition with our comprehensive guides.
Race Nutrition Calculator: Complete Guide
This evidence-based race nutrition calculator helps cyclists plan optimal fueling for road races, time trials, and gran fondos. It calculates personalized carbohydrate, fluid, and sodium targets based on your body weight, race duration, environmental conditions, and preferred nutrition strategy.
Key Features
- • Evidence-based carbohydrate calculations (30-120 g/hour)
- • Sweat rate estimation based on temperature and intensity
- • Sodium balance optimization for different sweat profiles
- • Time-stamped fueling schedule with specific product recommendations
- • GI risk assessment to prevent stomach issues during racing
The Science Behind Race Nutrition
Carbohydrate Oxidation and Absorption
During high-intensity cycling, your body primarily relies on carbohydrates for fuel. The rate at which you can absorb and oxidize carbohydrates is limited by intestinal transport mechanisms. Research by Jeukendrup and colleagues has established key guidelines:
- Single carbohydrate source (glucose/maltodextrin): Maximum oxidation rate of approximately 60 g/hour
- Multiple transportable carbohydrates (glucose + fructose): Can achieve 90+ g/hour when combined in optimal ratios
- Optimal glucose:fructose ratio: Approximately 1:0.8 for maximum absorption
Duration-Based Carbohydrate Guidelines
| Race Duration | Recommended Intake | Notes |
|---|---|---|
| < 1 hour | 0-30 g/hour | Mouth rinse may be sufficient |
| 1-2 hours | 30-60 g/hour | Single carb source adequate |
| 2-3 hours | 60-90 g/hour | Multiple transportable carbs recommended |
| > 3 hours | Up to 90-120 g/hour | Requires gut training and optimized products |
Hydration Science
Sweat Rate Estimation
Sweat rate varies significantly between individuals and conditions. The ACSM (American College of Sports Medicine) provides guidelines that form the basis of our estimation model:
Typical Sweat Rates by Temperature:
- • Cool conditions (<15°C): 0.3-0.6 L/hour
- • Moderate conditions (15-25°C): 0.5-1.0 L/hour
- • Hot conditions (>25°C): 0.8-1.5+ L/hour
Factors like body size, fitness level, and intensity further affect individual sweat rates.
Fluid Replacement Guidelines
The goal is to prevent excessive dehydration (>2% body mass loss) while avoiding overdrinking. Research suggests replacing 60-80% of sweat losses is optimal for most athletes during exercise.
Sodium and Electrolytes
Sweat sodium concentration varies widely between individuals (300-1500 mg/L). The calculator accounts for this variation:
| Sweater Type | Estimated Sodium Concentration | Indicators |
|---|---|---|
| Light sweater | ~400 mg/L | Minimal salt residue on skin/clothes |
| Average | ~700 mg/L | Some white marks on dark clothing |
| Salty sweater | ~1000 mg/L | Heavy salt stains, gritty skin feeling |
Drink Concentration and GI Tolerance
The concentration of carbohydrates in your drinks affects gastric emptying and absorption:
- 4-6% (isotonic): Optimal gastric emptying, well tolerated
- 6-8% (mildly hypertonic): Generally well tolerated
- 8-10%: May slow gastric emptying, increased GI risk
- >10%: High risk of GI distress, consider diluting
Pre-Race Nutrition
Carbohydrate Loading
For events lasting more than 90 minutes, carbohydrate loading can maximize glycogen stores:
- 24-48 hours before: 7-12 g/kg body weight per day
- Pre-race meal (3-4 hours before): 1-4 g/kg body weight
- Final top-up (30-60 min before): 0.5-1 g/kg (optional)
How to Use This Calculator
Step 1: Enter Rider Profile
Your body mass is essential for calculating nutrition needs. FTP helps estimate intensity, and sweat data (if known) improves hydration accuracy.
Step 2: Set Event Details
Select your race type, duration, and environmental conditions. Temperature and humidity significantly affect sweat rate and hydration needs.
Step 3: Choose Your Strategy
Conservative strategies are safer for beginners; aggressive strategies require gut training. Set your fluid and sodium replacement targets based on your experience.
Step 4: Select Products
Add the nutrition products you plan to use. The calculator will optimize your intake based on the carbohydrate, sodium, and fluid content of each product.
Step 5: Review Your Plan
Get a complete nutrition plan with time-stamped fueling schedule, product checklist, and risk assessments. Print it for race day reference.
Scientific References
Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 44(Suppl 1), S25-S33.
Thomas, D.T., Erdman, K.A., & Burke, L.M. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics, 116(3), 501-528.
Sawka, M.N., et al. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377-390.
Jeukendrup, A.E. (2008). Carbohydrate feeding during exercise. European Journal of Sport Science, 8(2), 77-86.
Baker, L.B., & Jeukendrup, A.E. (2014). Optimal composition of fluid-replacement beverages. Comprehensive Physiology, 4(2), 575-620.
Important Considerations
Test Your Plan Before Race Day
Individual responses to nutrition during exercise vary significantly. Always test your nutrition plan in training before implementing it in a race. Key factors to monitor:
- • Gut tolerance for your target carbohydrate intake
- • Preference for specific products and flavors during effort
- • Timing that works with your race intensity and course profile
- • Sodium needs based on your individual sweat composition
Gut Training
If you want to use aggressive carbohydrate intake rates (80+ g/hour), you need to train your gut. Start with lower intakes and gradually increase over 2-4 weeks of training. The gut adapts to higher carbohydrate intake with practice, improving absorption capacity and reducing GI distress risk.
About Me
Jonas
I have been a cyclist for over 10 years and I built this calculator to help cyclists like you and me with training and racing. This nutrition calculator is based on the latest sports science research to help you fuel optimally for your races.