Fat adaptation refers to the metabolic state where the body efficiently oxidises fat for energy at higher exercise intensities than normal. At low intensities (Zone 1-2), fit endurance athletes burn predominantly fat; less trained athletes burn more carbohydrate even at low intensities. Zone 2 training (prolonged moderate exercise) is the primary stimulus for fat adaptation — it increases mitochondrial density and fat oxidation enzymes. Some athletes pursue ketogenic or low-carbohydrate diets to enhance fat adaptation, though evidence for performance benefits is mixed. Fat adaptation conserves glycogen for high-intensity efforts.
Key points
- Efficient fat use at moderate intensities
- Developed through Zone 2 training
- Increases mitochondrial density
- Conserves glycogen for high-intensity efforts