14 Days Before Wuling: High-Carb Training vs. Low-Carb Adaptation—Which Strategy Wins?

The Wuling westbound route covers 55K with 3,275m of climbing, and most amateur riders finish in 4-6 hours. For such a long, moderate-intensity race, the fuel strategy is critical. In the 14 days before the race, should you load up on glycogen (high-carb) or train for fat adaptation (low-carb)?

The Scientific Basis of the Two Strategies

High-Carb Loading

• Gradually increase carbohydrate ratio to 60-70% of daily calories over the 14 days before the race
• “Carb Loading” in the final 3 days: 8-10 g/kg body weight
• Goal: maximize muscle and liver glycogen stores (approximately 600-800g)

Low-Carb High-Fat (LCHF) Adaptation

• Reduce carbohydrates to < 100g per day (< 20% of total calories) for 6-14 days before the race
• Increase fat ratio to 60-75%
• Goal: raise the Fatmax rate, allowing the body to rely more on fat at moderate intensity

Breaking Down the Energy Demands of Wuling

Assuming a 65kg rider completes the westbound Wuling in 5 hours:

• Average power: 180-220W
• Intensity: approximately 65-75% FTP (near the upper end of Zone 2 to Zone 3)
• Total calorie expenditure: approximately 3,000-4,000 kcal
• Heart rate zone: predominantly 140-160 bpm

This intensity range is exactly the sweet spot where fat and carbohydrate are burned in crossover—below 70% intensity, fat can contribute up to 50% of energy, but above 75% FTP, glycogen usage rises sharply.

What Do the Studies Say?

Burke et al. (2017) study on elite race walkers found:

• The LCHF group increased Fatmax by 38% after 3 weeks, but pedaling efficiency dropped 5% at intensities above 80%
• The high-carb group outperformed the LCHF group by 2-4% in time trials

Volek et al. (2016) study on ultra-endurance runners:

• Those adapted to LCHF for 6+ months reached a fat oxidation rate of 1.5 g/min per hour (vs. 0.7 g/min for the high-carb group)
• But the advantage only holds if race intensity stays below 65% VO2max

Practical Recommendations for Wuling

Based on the evidence above, here are recommendations for different types of riders:

Profile A: Goal is to “Finish” (6+ hours)

• Recommended: LCHF adaptation + carb refueling in the final 3 days before the race
• This pace keeps you below 60% FTP most of the time, where fat contribution is high
• Gradually increase carbs to 5-6 g/kg in the 72 hours before the race to avoid full ketosis compromising high-intensity surges

Profile B: Goal is to “Break 5 Hours”

• Recommended: traditional high-carb strategy
• This intensity (70-75% FTP) depletes glycogen rapidly
• Maintain 55-60% carbohydrate ratio for 14 days before the race, then Carb Load to 8-10 g/kg in the final 3 days
• Consume 60-90g of carbs per hour during the race

Profile C: Goal is to “Break 4 Hours”

• Must use the high-carb strategy
• Intensity approaches 80% FTP, where glycogen is the primary fuel
• Consume 10-12 g/kg body weight of carbs in the final 3 days before the race
• Use a “dual-source carb” (glucose + fructose) approach at 90-120 g/hr during the race

14-Day High-Carb Glycogen Loading: Execution Details

Day 14-8 (Foundation Phase):

• Carbohydrate ratio: 55-60% (5-6 g/kg)
• Maintain normal training volume, with 2 Sweet Spot sessions during the week

Day 7-4 (Progressive Accumulation):

• Increase carbs to 6-7 g/kg
• Reduce training volume by 20%, but keep 1 intensity session

Day 3-1 (Carb Loading):

• Push carbs to 8-10 g/kg
• Food choices: white rice, sweet potatoes, bananas, white toast, sports drinks
• Avoid: fried foods, high-fiber vegetables (gas-producing), chili peppers
• Body weight will increase by 1-2 kg (each gram of glycogen stores 3 grams of water)—this is normal

14-Day Low-Carb Adaptation: Execution Details

Day 14-8 (Induction Phase):

• Carbs < 50g/day; “Keto Flu” (fatigue, dizziness) may occur
• Increase electrolytes: sodium 3-5g, potassium 3-4g, magnesium 400mg

Day 7-3 (Adaptation Phase):

• Carbs: 50-100g/day
• Heart rate zones shift downward; a 5-10 bpm increase at the same intensity is normal

Day 2-1 (Refueling Phase, if using Train Low Compete High):

• Gradually increase carbs to 6-8 g/kg in the 48 hours before the race
• Preserve the fat-adaptation advantage while topping up glycogen

Conclusion

For 90% of amateur Wuling challengers, the traditional high-carb strategy remains the safer choice. Full LCHF adaptation requires at least 6 weeks to establish; cramming it into 14 days will actually hurt high-intensity performance.

If you have been on a long-term low-carb diet and your intensity falls within 60-70% FTP, you can maintain your strategy and do a light carb refuel in the 48 hours before the race. But if you are used to a high-carb diet, do not suddenly switch in the 14 days before the race—that is the fastest way to ruin your race.

Related Reading

• 24-Hour Eating Timeline the Day Before Wuling: Hour-by-Hour Carb Stacking Schedule
• 2-Week Post-Wuling Recovery Training Rhythm: Bridging from Low-Intensity Rolling to Your Next Target Race
• Timing Nutrition for Mountain Riding: Carb Supplementation Strategies Before, During, and After Climbs
• Climb Fueling Timing: Designing Carb Supplementation Points for Long Climbs