Achten & Jeukendrup 2004, Optimizing fat oxidation through exercise and diet

Nutrition 20(7-8):716-727. Review of the determinants of whole-body fat oxidation during exercise. Fat oxidation rate rises from low to moderate intensity, peaks, then falls as intensity climbs and carbohydrate takes over; the intensity of peak rate is termed FATmax, found at roughly 63% of VO2max in trained men in the authors’ own data and lower in untrained people. Fat oxidation is blunted by high carbohydrate availability (raised insulin and glycogen) and by high exercise intensity, and is raised by endurance training. Moderate.