Zone 2 training is often labeled as “fat burning,” but what does that actually mean in real-world performance? Should athletes, hunters, and endurance enthusiasts be eating more fat during long efforts? Or is the body primarily relying on stored energy systems regardless of what you eat?

In this episode of the Valley to Peak Nutrition Podcast, we break down one of the most misunderstood concepts in endurance nutrition: fat as fuel. We explore whether the body is using dietary fat or stored body fat during low-intensity exercise, how carbohydrates still play a critical role, and why it’s never as simple as “fat vs carbs.”

You’ll learn how energy systems actually interact during Zone 2 training, multi-day efforts, and long-duration mountain objectives—and why relying on a single fuel source can limit performance.

If you’ve ever wondered how to properly fuel Zone 2 training, ultras, backcountry hunts, or long mountain days, this episode will give you the clarity you need.

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• What “fat as fuel” actually means in Zone 2 training

• The difference between stored body fat and dietary fat

• How the body actually breaks down and uses fat for energy

• Why fat and carbohydrates are always used together (not separately)

• The role of intramuscular triglycerides in endurance performance

• Why muscle glycogen still matters—even at low intensities

• The real timeline for dietary fat to become usable energy

• Why higher intensity changes everything about fuel usage

• How carbohydrate supports fat metabolism (“fat burns in a carbohydrate flame”)

• Why calorie balance—not macronutrient manipulation—drives fat loss

• Zone 2 training is not 100% fat-burning—it’s a blend of fat and carbohydrate use

• Most fat used during exercise comes from stored body fat, not what you just ate

• Dietary fat takes hours to become usable fuel during activity

• Carbohydrates are essential for higher intensity and mental performance

• Fat and carbs work as a system—not competing fuel sources

• Endurance athletes

• Trail runners & ultrarunners

• Backcountry hunters and hikers

• Cyclists and hybrid athletes

• Anyone training in Zone 2 or long-duration efforts