Carb Loading for Trail Running: Filling Your Tank Before the Start

Carbohydrate loading before a trail run: concept of glycogen storage

We talk a lot about 60, 90, or 120g of carbohydrates per hour during a race. The fuel you carry at the start deserves the same attention. Scientific studies have recently quantified this leverage, and the amounts might surprise you.

Understanding Glycogen and Carb Loading

Glycogen is the stored carbohydrate in your muscles and liver. It's limited, and it's what powers your sustained climbs and surges. A well-executed carb load allows you to start the race with these stores at their maximum.

Carb loading is part of your tapering. You reduce training load, increase carbohydrates, and the two work together. Fresh legs and full reserves at the start line: that's what we're aiming for in the final days.

Nutritional strategy for carbohydrate loading in trail running

Calculating Your Carbohydrate Needs

We calculate in grams of carbohydrates per kilogram of body weight. For a 65 kg athlete, 8g/kg represents 520g of carbohydrates per day. 100g of raw rice provides about 75 to 80g. Do the math once, and you'll quickly understand why carb loading is prepared over two days.

Concrete Examples of Quantities

  • 60 kg athlete: 480 to 600g of carbohydrates per day (depending on 8-10g/kg target)
  • 70 kg athlete: 560 to 700g of carbohydrates per day
  • 80 kg athlete: 640 to 800g of carbohydrates per day

48-Hour Carb Loading Protocol

To optimize your glycogen reserves before your next long objective, here's the protocol to follow:

  • Calculate your target: your weight × 8 to 10g of carbohydrates per day
  • Start carb loading 36 to 48 hours before the start
  • Distribute over 5 to 6 meals/snacks: rice, pasta, potatoes, bread, compotes, honey
  • Supplement with carbohydrate drinks to reach the target while keeping your stomach light
  • Lighten your sessions: short easy run and a few strides
  • Test the protocol before a long training run or a preparatory race
Nutrition and diet for trail runners: carbohydrate loading guide

Implementation and Self-Assessment

Do you know how many grams of carbohydrates you ate in the 48 hours before your last race?

Take your weight, multiply it by 8, and compare it with what you actually ate. The gap between theory and practice is often significant. This awareness is the first step towards better nutritional preparation.

Why Test Before Race Day

Never try a new nutritional protocol on the day of your main race. Test your carb loading on a long training run or a preparatory race. This way, you'll adjust quantities, identify foods that work well for you, and arrive at the start line with confidence.

— Antoine, Baptiste, and Etienne from TRL