You need carbs when:

A workout is longer than 1hr.

It’s a “workout” not easy miles. For example: Intervals, Tempo, Threshold VO2 Max, Long Run/Ride.

You’re in an intense block and you are struggling to recover..

You can use our carb calculator to work out how many carbs/Vert you need.

Carb Calculator

When should you utilize intra-workout or pre-workout carbs is one of the most common questions we get. In a classic lawyer response the answer is: it depends. With the variables in general being:

  • The length of the workout
  • The specific workout (Interval, Tempo, long run, easy run).
  • The intensity of the workout.
  • How many carbs you eat in general.
  • Total training volume.

Length of the Workout:

For shorter workouts, those less than 60min, intra-workout carbs are generally not necessary. If it’s a particularly intense workout and you are fatigued, it might help though.

For events 60 mins or less, 30g/hr is sufficient, for 60-90 mins 60g/hr of carbs is sufficient, above 90mins, you can increase this to 90g/hr. Some people are trialing 120 -150g/hr but this warrants gut training and practice before race day.

Specific Workout Type:

In general, you won’t need carbs for easy runs/rides/swims.

Interval training, VO2 max, and Long endurance efforts should be fueled. Not only will it sustain your effort during your workout, but it will enhance recovery.

Overall Carbohydrate Intake:

Your daily carbohydrate consumption habits should also inform your decision. Individuals with higher carbohydrate intake in their regular diet may have sufficient glycogen stores to support workouts without additional pre-workout carbs.

Conversely, those on lower carbohydrate diets will benefit from intra-workout carbs.

Total Training Volume:

If you’re running/cycling/swimming double days all week, you may benefit from intra-workout carbs as it may be difficult to eat enough to recover before your next session. It’s a good tip to weigh yourself at the start of your block, and if you start losing weight, up your carbs and calories.

April 12, 2024 — Ben Paris