Thoughts on “training body to use fat instead of glucose for fuel”

Nutrition Q&A [Moderated]
1

Hi, I’m doing a cycling training program using TrainerRoad, and in the endurance workouts they talk about how long low intensity rides “teach your body to use fat instead of sugar for fuel.” Their recommendation is to do low intensity fasted endurance rides regularly.

Is there any scientific merit in this claim? Based on what I’ve read here, I don’t think there is, but I wanted to check with a trusted source.

2

There are a few ways to increase fatty acid oxidation rates:

  1. Increase dietary fat intake (relatively small effect)
  2. Exercise at low intensity, like <30-40% of VO2Max
  3. Eat a low carbohydrate or ketogenic diet (relatively small effect)

Your body is going to use sugar as the predominant source of fuel for almost any endurance workout you would perform. Additionally, the data on train low (low carb) and compete high (carb load) is nearly universal in showing no real benefit for performance outcomes. Some surrogate markers change, but this didn’t lead to increase performance.

-Jordan