Carb Loading Done Right: Beyond the Old Pasta Dinner
The old pasta dinner is just the beginning. Learn the science of carb loading and how to maximize your glycogen stores for race day success.
Quick Answer
Modern carb loading means 48–72 hours of 8–10 g/kg carbs, tapering exercise, and staying hydrated — not just a pasta dinner the night before.
The night before your race, you sit down to a massive plate of pasta. You're carb loading.
But here's the truth: the old pasta dinner is just one small part of modern carb loading.
The science has evolved. Here's how to carb load properly in 2026.
What Is Carb Loading?
Carb loading (glycogen supercompensation) is the process of maximizing muscle glycogen stores before an endurance event.
Your muscles can store 400–500 grams of glycogen. Carb loading can increase this by 50–100%.
The Evolution of Carb Loading
The classic 1970s protocol involved a week of exercise depletion followed by a week of high-carb eating. It worked, but it was miserable.
Modern carb loading is simpler and more effective:
| Feature | Classic Protocol | Modern Protocol |
|---|---|---|
| Duration | 7 days | 48–72 hours |
| Exercise | Depletion phase | Taper only |
| Carb intake | Very high | 8–10 g/kg/day |
| Effectiveness | 50–100% increase | Similar increase |
| Athlete experience | Difficult | Much easier |
When to Start Carb Loading
Start 2–3 days before your race, when training volume has already decreased.
- 3 days out: Begin increasing carbs gradually
- 2 days out: High-carb meals, maintain taper
- 1 day out: Continue carb intake, keep meals light
- Race morning: Small top-up meal 3–4 hours before
How Many Carbs Do You Need?
Target 8–10 grams of carbs per kilogram of body weight per day during the loading phase:
| Feature | Body Weight | Daily Carbs (8 g/kg) | Daily Carbs (10 g/kg) |
|---|---|---|---|
| 60 kg (132 lb) | 480 g | 600 g | |
| 70 kg (154 lb) | 560 g | 700 g | |
| 80 kg (176 lb) | 640 g | 800 g | |
| 90 kg (198 lb) | 720 g | 900 g |
What to Eat
Choose easily digested, low-fiber carbohydrates:
- White rice, pasta, and bread
- Oatmeal and low-fiber cereals
- Potatoes and sweet potatoes
- Bananas, applesauce, and fruit juice
- Sports drinks and carb drink mixes
- Rice cakes, bagels, and crackers
What to Avoid
- High-fiber foods (whole grains, beans, cruciferous vegetables)
- Heavy fats (fried foods, heavy sauces, large portions of nuts)
- Excess protein (fills you up before carbs)
- New or unfamiliar foods (risk of GI distress)
- Alcohol (impairs glycogen storage)
Hydration During Carb Loading
Glycogen binds with water — about 3 grams of water per gram of glycogen. You may gain 1–2 kg during carb loading, which is normal and expected.
- Drink to thirst throughout the day
- Include electrolytes, especially sodium
- Avoid overhydration (clear urine is not the goal)
- Continue sipping fluids before bed
Race Morning Top-Up
After an overnight fast, liver glycogen is depleted. Add a final carb meal 3–4 hours before the race:
- 1–4 g carbs/kg body weight (70–280 g for most)
- Low-fiber, low-fat, familiar foods
- Small protein portion if desired
- Sip fluids with electrolytes
Common Carb Loading Mistakes
- Starting too late (night before isn't enough)
- Eating too much protein or fat, crowding out carbs
- Skipping hydration
- Trying new foods
- Not tapering exercise adequately
Get your personalized carb loading plan.
Download MAVRFrequently Asked Questions (FAQ)
Will carb loading make me gain weight?
You may gain 1–2 kg from water bound to glycogen. This is temporary and normal. It shows your stores are full.
What if I can't eat that many carbs?
Do your best — even a partial carb load helps. Focus on easily digested foods and spread intake across the day.
Can I carb load for a half marathon?
For most runners, carb loading isn't necessary for a half marathon unless racing hard in hot conditions. Focus on pre-race meals instead.
Does carb loading work for cycling too?
Yes. Any endurance event over 90 minutes benefits from carb loading — cycling centuries, Ironman, ultra-events, etc.
How does MAVR help with carb loading?
MAVR calculates your carb targets, suggests meal timing, and reminds you when to start loading based on your race date.