Carb Loading for Triathlon: The Complete Guide to Race-Day Fuel

Why Carb Loading Actually Works (The Science Made Simple)

Let me be honest with you—I used to think carb loading was just an excuse to eat pasta guilt-free. Then I learned the science behind it, and everything changed.

Your muscles store energy as glycogen, which is essentially chains of glucose molecules. Think of it as your body’s premium fuel tank. Research shows your body can store about 2,000 calories of glycogen, but here’s the kicker—that’s only enough for about 90 minutes of intense exercise.

Most triathlons last well beyond 90 minutes, which is why as exercise duration extends beyond 90 minutes, the body begins to switch from predominantly using fat for fuel to carbohydrates. Without proper carb loading, you’re essentially starting a road trip with half a tank of gas.

The Modern Approach: Beyond the Pasta Party

The game has changed. The proper way to carb load involves gradually increasing your carbohydrate intake to about 10 grams per kilogram of body weight each day, starting three days before your endurance event. But let’s break this down into something you can actually use.

Your Step-by-Step Carb Loading Protocol

Timing is Everything

36-48 Hours Before Race: This is your golden window. Any earlier and you’ll just store excess calories as fat. Any later and you won’t maximize glycogen stores.

The Numbers Game

Body Weight	Daily Carb Target	Example
60kg (132 lbs)	480-720g	2-3 cups rice + extras
70kg (154 lbs)	560-840g	3-4 cups rice + extras
80kg (176 lbs)	640-960g	4-5 cups rice + extras

The Right Foods: Your Carb Loading Arsenal

Here’s where most people get it wrong. With carb loading, generally, the simpler the carb, the better. So this is one of those times when you absolutely should go for white bread over wholemeal bread and white rice over brown rice. I know, I know—it goes against everything you’ve been told about “healthy eating.” But race week isn’t about health; it’s about performance.

A Day in the Life: Sample Carb Loading Menu

Let me show you what a practical carb loading day looks like for a 70kg athlete (targeting ~740g carbs):

Meal	Foods	Carbs (g)
Breakfast	Large bowl cereal + milk + 2 toast with jam + banana	170
Mid-Morning	2 bagels with honey + energy bar	120
Lunch	Large pasta portion + tomato sauce + fruit juice	175
Afternoon	Muffin + banana	60
Dinner	Large rice portion + chicken + sports drink	155
Evening	Cereal + milk	80

Professional Insights: What Elite Athletes Are Doing

The sport is evolving rapidly. In professional triathlon, Magnus Ditlev can consume up to 170 grams of carbs per hour while racing, and Sam Long publicly admitted he can consume 150 grams. While these numbers are for race-day fueling, they show how seriously the pros take carbohydrate strategy.

What does this mean for you? Start practicing high-carb strategies now. Your gut needs training too.

The Biggest Carb Loading Mistakes (Learn from My Failures)

Beyond the Basics: Advanced Strategies

The Taper Connection

Carb loading works best when paired with reduced training volume. Your muscles need to be relatively fresh to store maximum glycogen. This is why the final week before your race should be about topping off your energy stores, not depleting them.

Individual Variations

Everyone’s different. Some athletes can handle 12g per kg, others feel better at 8g. Female triathletes consumed significantly more carbohydrate on the morning before race start when corrected for body mass, suggesting gender may play a role in optimal strategies.

Race Day: Putting It All Together

Your carb loading success isn’t just about the days leading up to your race—it’s about seamlessly connecting to your race-day fueling strategy. Think of carb loading as filling up your tank, and race-day nutrition as keeping it topped off.

The research shows that the average carbohydrate intake during an Ironman distance triathlon was 1.0 g · kg BW−1 · h−1 in female triathletes and 1.1 g · kg BW−1 · h−1 in male triathletes. This connects directly to your carb loading strategy.

Expert Resources for Deeper Learning

Want to dive deeper into the science? Check out these authoritative sources:

• Precision Fuel & Hydration’s Evidence-Based Approach
• Scientific Triathlon’s Research-Based Nutrition Guide
• Nutrition for Triathlon’s Practical Guide

Remember: This information is for educational purposes. For personalized nutrition advice, especially if you have health conditions or dietary restrictions, consult with a qualified sports nutritionist or registered dietitian.