Carb Loading for Cyclists – How to Maximize Glycogen Before Race Day
Evidence-based carb loading guide for cyclists. Learn the 24-48 hour protocol, best foods to eat, common mistakes to avoid, and how to maximize glycogen stores before your race.
What is carb loading and do you need it? Carb loading is a strategy to maximize muscle glycogen stores before endurance events. For races lasting 90+ minutes, it can delay fatigue and improve performance. This guide covers how to do it right.
Plan your complete race nutrition with our Cycling Race Nutrition Calculator.
Do You Need to Carb Load?
| Event Duration | Carb Loading Benefit | Recommendation |
|---|---|---|
| Under 60 min | Minimal | Normal eating is fine |
| 60-90 min | Small | Optional, moderate increase |
| 90 min - 3 hours | Moderate | Recommended |
| 3+ hours | Significant | Highly recommended |
| Ultra events (6+ hours) | Very significant | Essential |
For events under 90 minutes, your normal glycogen stores (plus good pre-race breakfast) are sufficient. For longer events, carb loading provides a meaningful performance edge.
How Carb Loading Works
Glycogen Storage Basics
Your body stores carbohydrates as glycogen:
| Location | Normal Stores | After Carb Loading |
|---|---|---|
| Muscle glycogen | 300-400g | 500-700g |
| Liver glycogen | 80-100g | 100-120g |
Carb loading can increase muscle glycogen by 50-100%, providing significantly more fuel before you need to rely heavily on external carbs.
The Adaptation Process
When you eat high carbohydrates after depletion or normal training:
- Muscles become more efficient at storing glycogen
- Each gram of glycogen stores with ~3g of water
- You may gain 1-2kg of "water weight" (this is good)
- Fully loaded muscles feel "full" and ready
The Modern Carb Loading Protocol
24-48 Hours Before
Forget the old 7-day depletion protocols. Modern sports science shows that 24-48 hours of high carb intake is sufficient.
Target intake: 7-12g carbs per kg body weight per day
| Body Weight | Low End (7g/kg) | High End (12g/kg) |
|---|---|---|
| 55 kg | 385g | 660g |
| 65 kg | 455g | 780g |
| 75 kg | 525g | 900g |
| 85 kg | 595g | 1020g |
Most athletes do well with 8-10g/kg. Go higher if you tolerate it and have a very long event.
Sample Carb Loading Day (70kg rider, ~600g carbs)
Breakfast (150g carbs):
- 100g oatmeal with honey: 70g
- 2 slices toast with jam: 50g
- Banana: 25g
- Orange juice (250ml): 25g
Snack (50g carbs):
- Bagel with honey: 50g
Lunch (150g carbs):
- Large pasta serving (150g dry): 110g
- Bread roll: 25g
- Fruit: 15g
Snack (50g carbs):
- Energy bar: 40g
- Fruit: 10g
Dinner (150g carbs):
- Rice (150g dry): 120g
- Bread: 25g
- Low-fiber vegetables: 5g
Evening snack (50g carbs):
- Toast with jam: 30g
- Sports drink: 20g
Total: ~600g carbs
Best Foods for Carb Loading
Ideal Carb Loading Foods
| Food | Carbs per 100g | Why It Works |
|---|---|---|
| White rice (cooked) | 28g | Easy to digest, versatile |
| Pasta (cooked) | 25g | High volume, satisfying |
| White bread | 49g | Quick carbs, easy to add |
| Bagels | 53g | Dense carbs, portable |
| Oatmeal (cooked) | 12g | Familiar, nutritious |
| Bananas | 23g | Convenient, potassium |
| Pancakes | 35g | Easy to eat large amounts |
| Pretzels | 80g | Low fat, pure carbs |
| Sports drinks | 6-8g | Easy calories |
| Rice cakes | 78g | Light, versatile |
Foods to Limit During Carb Loading
| Food Category | Why Limit |
|---|---|
| High-fiber grains | Bloating, GI issues |
| Raw vegetables | Gas, discomfort |
| Legumes | Gas, bloating |
| High-fat foods | Slow digestion, less carb space |
| High-protein meals | Displaces carbs |
| Fatty sauces/dressings | Calories without carbs |
Quick Carb Additions
When you need to boost carbs without eating more volume:
| Addition | Carbs Added |
|---|---|
| Honey (1 tbsp) | 17g |
| Maple syrup (1 tbsp) | 13g |
| Jam (1 tbsp) | 13g |
| Sports drink (500ml) | 30-40g |
| Fruit juice (250ml) | 25-30g |
| Sugar in coffee | 4g/tsp |
The Day Before Your Race
Meal Timing
| Meal | Timing | Focus |
|---|---|---|
| Breakfast | Normal time | 100-150g carbs |
| Snack | Mid-morning | 30-50g carbs |
| Lunch | Normal time | 100-150g carbs |
| Snack | Afternoon | 30-50g carbs |
| Dinner | Earlier than usual | 100-150g carbs |
| Evening snack | 2-3 hours before bed | 30-50g carbs |
Dinner Considerations
- Eat earlier than usual (6-7pm for next-day race)
- Choose familiar, proven foods
- Lower fiber than your normal diet
- Moderate protein (you still need some)
- Low fat for easy digestion
- Include sodium for fluid retention
Hydration During Carb Loading
- Drink normally—don't force excessive fluids
- Glycogen storage pulls water into muscles (good)
- Urine should be light yellow
- Include some sodium to help retain fluids
Race Morning
Your pre-race breakfast is the final piece of the fueling puzzle.
See our complete guide: What to Eat Before a Cycling Race
Quick Race Morning Summary
| Timing | Carbs | Example |
|---|---|---|
| 3-4 hours before | 1-4g/kg | Normal breakfast |
| 1-2 hours before | 0.5-1g/kg | Toast, banana |
| 30-60 min before | 0-0.5g/kg | Gel, sports drink |
Common Carb Loading Mistakes
Mistake 1: Too Much Fiber
Whole grains are healthy but cause bloating. Switch to refined carbs 48 hours before your event.
Instead of: Whole wheat bread, brown rice, high-fiber cereal Choose: White bread, white rice, low-fiber cereals
Mistake 2: Too Much Fat
Fat slows digestion and takes up stomach space you need for carbs.
Instead of: Creamy pasta sauces, fried foods, cheese-heavy meals Choose: Tomato-based sauces, plain cooking methods, minimal cheese
Mistake 3: Trying New Foods
Race week is not the time for that new restaurant. Stick to familiar, tested foods.
Mistake 4: Not Enough Total Carbs
Many cyclists underestimate how much they need. 600-800g of carbs is a LOT of food. Plan it out.
Mistake 5: Feeling Bloated = Doing It Wrong
Some bloating and weight gain is expected and normal. The extra water is stored with glycogen and will help during the race.
Mistake 6: Cutting Calories
Some athletes worry about weight gain from carb loading. Accept the temporary 1-2kg increase—it's mostly water bound to glycogen, and it helps performance.
Mistake 7: Drinking Too Little
Glycogen storage requires water. If you restrict fluids, you limit how much glycogen you can store.
Carb Loading for Different Events
Road Races (3-4 hours)
- Full 48-hour protocol beneficial
- 8-10g/kg per day
- Focus on race-day breakfast timing
Gran Fondos (4-6 hours)
- Full protocol highly recommended
- 10-12g/kg if tolerated
- Consider carb loading for 2 full days
Stage Races
- Carb load before stage 1
- Maintain high carb intake throughout
- Recovery nutrition becomes carb loading for next day
Gravel Events (4-8 hours)
- Full protocol essential
- Higher end of carb range (10-12g/kg)
- May not have many feed opportunities
The Timeline
7 Days Before
- Train normally
- Eat normally
- Note any foods that cause issues
3-4 Days Before
- Taper training (reduced volume)
- Normal to slightly elevated carbs
- Stay hydrated
48 Hours Before
- Begin carb loading (7-12g/kg/day)
- Reduce fiber intake
- Reduce fat intake
- Limit alcohol
- Increase refined carbs
24 Hours Before
- Continue high carb intake
- Very low fiber
- Low fat
- Early dinner
- Good hydration
Race Morning
- Pre-race meal 3-4 hours before
- Top-ups as needed
- Race!
Monitoring Success
Signs Carb Loading Is Working
- Weight gain of 1-2kg (mostly water)
- Muscles feel "full" or pumped
- Good energy levels
- No excessive bloating or GI issues
- Light yellow urine
Signs Something's Wrong
- Severe bloating or discomfort
- Significant GI issues
- Feeling sluggish or heavy
- Can't finish meals
If having issues, reduce fiber more, choose simpler foods, and don't force uncomfortable amounts.
Key Takeaways
- Carb load for events 90+ minutes—shorter events don't need it
- Target 7-12g carbs per kg body weight for 24-48 hours before
- Choose low-fiber, low-fat, high-carb foods (white rice, pasta, bread)
- Accept temporary weight gain—it's water bound to glycogen
- Practice before important events to know what works for you
Plan Your Complete Race Nutrition
Carb loading is just the start. Use our Cycling Race Nutrition Calculator to plan your pre-race meal, in-race fueling, and complete hydration strategy.
Related Calculators
- Cycling Race Nutrition Calculator - Complete race planning
- Cycling Calorie Calculator - Energy needs
- FTP Calculator - Intensity planning
Related Articles
- What to Eat Before a Cycling Race - Race morning nutrition
- Cycling Race Nutrition Guide - Complete overview
- How to Fuel During Long Rides - In-race fueling
- How Many Carbs Per Hour Cycling - During-race carb needs