race-nutrition

name	race-nutrition
description	Evidence-based nutrition and hydration protocols for trail/ultra races. Covers gut training, race-day fueling strategies, carbohydrate periodization, hydration/sodium protocols, and recovery nutrition.

Race Nutrition

When to use this skill

Use this skill when the request involves:

• Planning race-day fueling strategies (carbohydrate intake, hydration, sodium)
• Gut training protocols in preparation for races
• Pre-race carbohydrate loading strategies
• Post-race recovery nutrition
• Troubleshooting GI issues during training or racing
• Determining optimal CHO/fluid/sodium intake rates

Core principles: "Fuel for the work required"

Evidence-based approach: Based on recent ultra-endurance nutrition research (Gateway Innovation 2025, Journal of Sports Medicine 2013, ACSM/IOC position stands)

Key concept: Trainable gut capacity

• Athletes can LEARN to absorb higher carbohydrate loads
• Progressive gut training over 4-6 weeks increases CHO tolerance
• SGLT1 (sodium-glucose transporter) capacity increases with training

Gut Training Protocols (4-6 weeks pre-race)

Progressive CHO tolerance building

Purpose: Train the gut to absorb race-day CHO targets without GI distress

Protocol:

Week 1 (long run): 20 g/h CHO
Week 2 (long run): 30 g/h CHO
Week 3 (long run): 40 g/h CHO
Week 4 (long run): 50 g/h CHO (or race target)
Week 5: Race-level testing (simulate race fueling)
Week 6 (taper): Light testing only

Implementation details:

• Test on long runs (2+ hours minimum)
• Use actual race products (gels, drink mix, real food)
• Start CHO intake within first 15-20 minutes of run
• Take CHO every 15-20 minutes (don't wait until "feeling hungry")

Monitoring:

• GI comfort scale: 0 (no issues) to 10 (severe nausea/cramping/bloating)
• Target: maintain GI comfort ≤3/10 throughout run
• If GI issues >5/10: reduce CHO next session, troubleshoot products

Red flags:

• Persistent nausea/vomiting during training fueling
• Severe bloating that doesn't improve with practice
• Diarrhea during or immediately after fueling sessions

→ If 2+ red flags: consult sports dietitian, consider alternative CHO sources (liquid vs gel vs real food)

Source: Journal of Sports Medicine (2013), Gateway Innovation (2025)

Race-Day Fueling Strategies

Carbohydrate intake targets

Duration-based recommendations:

< 6 hours (50-80 km ultras):

• Target: 40-50 g/h CHO
• Rationale: Sufficient for glycogen maintenance, lower GI risk

> 6 hours (80+ km, 24h+ events):

• Target: 50-60 g/h CHO (recreational)
• Target: 60-90 g/h CHO (elite or highly trained)
• Rationale: Higher oxidation rates, need multiple CHO sources

Practical delivery:

• Every 20 minutes: 10-15g CHO (1 gel, or 150-200ml sports drink 6-8%, or 1 date/fig)
• OR hourly package: ~50g CHO (1.5 gels + electrolyte drink, or 500ml sports drink 9-10% + 1 banana slice)

Example for 50K, 70kg athlete, 6-7h race:

• Pre-race (3h before): 1.5g/kg = 105g (porridge + honey + banana)
• During: 45g/h × 6.5h = ~300g total
  • Option 1: 2 gels/h (40g) + sports drink
  • Option 2: 1 gel/h + real food (banana, dates) + drink
  • Option 3: Only liquid nutrition (sports drink 8-10%)

Multiple carbohydrate sources:

• For >60g/h: use glucose + fructose combination (2:1 ratio ideal)
• Single CHO source (glucose only): saturates at ~60g/h
• Multiple transporters (glucose + fructose): can absorb 90g/h

Source: Gateway Innovation (2025), ACSM position stand

Hydration protocols

Fluid intake:

• Target: 450-750 ml/h
• OR: 150-250 ml every 20 minutes
• Adjust for:
  • Heat/humidity: ↑ toward 750 ml/h
  • Cold/altitude: ↓ toward 450 ml/h
  • Sweat rate (individual): use sweat test data if available

Practical strategies:

• Use handheld bottle, vest with soft flasks, or hydration pack
• Pre-mark bottles with time intervals (e.g., "drink by mile 5")
• Aid station strategy: drink 200-250ml at each station (if spaced ~30-45 min apart)

Monitoring hydration status:

• Urine color: pale yellow = adequate, dark amber = dehydrated
• Body weight change: aim for <2-3% loss during race
• Thirst: drink to thirst, but don't wait until "very thirsty"

Warning: Hyponatremia risk

• Overhydration + insufficient sodium = dangerous
• Symptoms: nausea, headache, confusion, swelling (hands/feet)
• Prevention: adequate sodium intake (see below)

Sodium (electrolyte) protocols

Sodium targets:

• Standard: 300-600 mg/h
• OR: 500-700 mg/L fluid
• Heat/high sweat rate: ↑ toward 600-700 mg/h

Practical delivery:

• Electrolyte tablets/capsules (e.g., SaltStick: 215mg Na per cap)
• Sports drink with electrolytes (check label for Na content)
• Real food (pretzels, salted nuts, broth at aid stations)

Example for 70kg runner, 6h race, moderate heat:

• Fluid: 600 ml/h × 6h = 3,600 ml
• Sodium: 500 mg/h × 6h = 3,000 mg
• Delivery: 600ml sports drink (500mg Na/L) + 1 electrolyte cap/h

Individual variation:

• "Salty sweaters" (white residue on clothes/skin): ↑ toward 700 mg/h
• Low sweat rate, cool conditions: can use 300-400 mg/h

Source: ACSM/IOC consensus, Gateway Innovation (2025)

Pre-Race Carbohydrate Loading

Evidence-based protocol (NOT the old "week-long" method)

Timeline: 36-48 hours before race

Carbohydrate target:

• 8-12 g/kg/day × 2 days
• Example for 70kg athlete: 560-840g/day

Practical implementation:

• Day -2: Normal breakfast, then ↑ CHO at lunch/dinner/snacks
• Day -1: High-CHO all meals (pasta, rice, bread, fruit, juice)
• Focus on familiar foods (avoid GI experimentation)

What this looks like (example for 70kg, target 600g/day):

• Breakfast: oatmeal (60g CHO) + banana (30g) + honey (20g) = 110g
• Snack: juice (40g) + energy bar (30g) = 70g
• Lunch: pasta (80g CHO) + bread (30g) + fruit (20g) = 130g
• Snack: smoothie (50g CHO) + dried fruit (30g) = 80g
• Dinner: rice (100g CHO) + potatoes (40g) + dessert (30g) = 170g
• Evening snack: cereal (30g) + juice (20g) = 50g
• Total: 610g CHO

Fiber management:

• Reduce fiber 24-36h before race (avoid whole grains, raw vegetables)
• Rationale: prevent GI issues during race

Pre-race meal (1-4h before start)

Carbohydrate target:

• 1-4 g/kg depending on timing and tolerance
• Closer to race: lower amount, more easily digestible
• Further from race: can be larger

Examples:

• 3-4h before: 3-4 g/kg (e.g., 210-280g for 70kg) — full meal (pasta, rice, oatmeal)
• 2-3h before: 2-3 g/kg (140-210g) — moderate meal (oatmeal + banana + honey)
• 1-2h before: 1-2 g/kg (70-140g) — light meal (toast + jam, energy bar + banana)

Avoid:

• High fat (slows digestion)
• High fiber (GI risk)
• New/untested foods
• Large protein portions (not needed pre-race)

Caffeine (optional):

• 3-6 mg/kg body weight 30-60min before start
• Example: 70kg athlete = 210-420mg (2-4 espressos or 1-2 caffeine gels)
• Benefits: ↑ alertness, ↓ perceived exertion, ↑ fat oxidation
• Test in training first!

Source: ACSM/IOC position stand

Post-Race Recovery Nutrition

Immediate recovery window (0-30 minutes)

Carbohydrate priority:

• Target: 1.0-1.2 g/kg body weight
• Example: 70kg athlete = 70-84g CHO
• Purpose: Rapid glycogen replenishment

Practical options:

• Recovery drink (e.g., chocolate milk: 500ml = 60g CHO + 16g protein)
• Gels + electrolyte drink
• Real food if tolerated (banana + bread + juice)

Protein addition (optional but beneficial):

• 15-25g protein with CHO
• Enhances muscle protein synthesis
• Ratio: 3:1 or 4:1 CHO:protein ideal

Extended recovery (2-24 hours)

Carbohydrate replenishment:

• First 4-6 hours: 1.0-1.2 g/kg every 2h (if quick recovery needed)
• OR: spread across meals at 6-10 g/kg/day total

Hydration:

• Drink 1.5L per kg body weight lost
• Example: lost 1kg during race → drink 1.5L over next 4-6h
• Include sodium to enhance fluid retention

Protein:

• 1.6-2.0 g/kg/day for muscle repair
• Distribute across 4-5 meals (20-40g per meal)

Anti-inflammatory foods (optional):

• Tart cherry juice: reduces muscle soreness
• Turmeric, ginger: natural anti-inflammatories
• Omega-3 (fish, walnuts, chia): supports recovery

Avoid:

• Alcohol (impairs recovery, dehydration)
• Excessive fat immediately post-race (slows CHO absorption)

Source: ACSM/IOC position stand

Common Mistakes & Troubleshooting

Mistake 1: Waiting until "feeling hungry" to eat

Problem: By then, glycogen depletion has already begun
Solution: Start fueling at 15-20 min, continue every 15-20 min regardless of hunger

Mistake 2: Not practicing race-day fueling

Problem: GI distress on race day
Solution: Use gut training protocol (4-6 weeks), test exact products

Mistake 3: Trying new products on race day

Problem: Unpredictable GI response
Solution: "Nothing new on race day" — only tested products

Mistake 4: Insufficient sodium intake

Problem: Hyponatremia, cramping, nausea
Solution: Target 300-600 mg/h, ↑ in heat/high sweat rate

Mistake 5: Overhydrating

Problem: Hyponatremia (dilution of blood sodium)
Solution: Drink to thirst + adequate sodium, don't exceed 750-800ml/h

Mistake 6: High-fiber pre-race meals

Problem: GI issues during race
Solution: Reduce fiber 24-36h before, focus on easily digestible CHO

Mistake 7: Relying only on aid station food

Problem: Timing gaps, unfamiliar food, insufficient CHO
Solution: Carry own nutrition, use aid stations as supplement

Individual Variation & Adaptation

Factors affecting requirements:

• Body weight: heavier athletes need more absolute CHO/fluid
• Sweat rate: measure via pre/post-run weight (1kg loss = 1L sweat)
• Heat/humidity: ↑ fluid needs, ↑ sodium needs
• Altitude: ↓ fluid needs (less sweat), ↑ CHO needs (higher metabolic rate)
• Pace/intensity: faster = higher CHO oxidation rate

Adaptation timeline:

• Gut CHO absorption: improves significantly in 4-6 weeks
• Fat oxidation capacity: develops over months (aerobic base training)
• Sweat rate adaptation: 1-2 weeks in new heat conditions

When to seek professional help:

• Persistent GI issues despite gut training
• History of hyponatremia
• Extreme sweat rates ("salty sweater")
• Pre-existing GI conditions (IBS, Crohn's, etc.)
• Weight loss >5% during races despite fueling

→ Consult sports dietitian (RD, CSSD credential)

Integration with Training Phases

Base Period: Low-intensity nutrition

• Opportunity for "train low, compete high" sessions (once/week)
• Practice fasted morning runs (Z1, <90 min) to enhance fat oxidation
• Most long runs: normal fueling to support volume

Build Period: Gut training phase

• Start 4-6 week gut training protocol
• Test all race-day products
• Practice aid station strategy (if applicable)

Specific Period: Race simulation

• Full dress rehearsal: race-day fueling on key long runs
• Test pre-race meal timing and composition
• Verify hydration strategy under race-specific conditions

Taper: Carb loading prep

• Week -2: normal nutrition
• Week -1: initiate carb loading (day -2, day -1)
• Pre-race meal: tested protocol, 1-4h before

Source: Ultrarunning Training Essentials (Koop), Gateway Innovation (2025)

Key Takeaways

1. Gut is trainable: 4-6 weeks progressive CHO loading prepares GI system
2. Start early, stay consistent: Begin fueling at 15-20min, continue every 15-20min
3. CHO targets: 40-50g/h (<6h), 50-60g/h (>6h), 60-90g/h (elite/>24h)
4. Hydration: 450-750ml/h + 300-600mg Na/h (adjust for conditions)
5. Carb loading: 8-12g/kg/day × 2 days (NOT week-long)
6. Recovery: 1.0-1.2g/kg CHO within 30min post-race
7. Nothing new on race day: Test everything in training

Remember: Nutrition is the "4th discipline" in ultra-endurance — neglecting it undermines all your training.