Understanding the factors that effect maximal fat oxidation.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing physiological mechanisms without systematic search methodology.
PubMed 29344008 · doi:10.1186/s12970-018-0207-1
What was done
The authors synthesized literature examining the physiological sources, regulatory mechanisms, and determinants of fatty acid oxidation and maximal fat oxidation (MFO) during exercise. The review evaluates the influence of exercise intensity, duration, training status, sex differences, and nutritional factors on cellular adaptations and substrate oxidation.
What was found
The abstract reports no empirical data or meta-analytic effect sizes. It describes that maximal fat oxidation occurs primarily at exercise intensities between 45% and 65% VO2max. Beyond this crossover point (~65% VO2max), limitations in fatty acid transport across cellular and mitochondrial membranes restrict fat oxidation, and carbohydrate oxidation predominates. Adaptations that enhance fat oxidation rates are facilitated by long-duration endurance training (>2 hours).
Why it matters
Understanding the physiological determinants and crossover points of fat oxidation provides a metabolic basis for optimizing endurance training and nutritional strategies.
Limits
This is a narrative review rather than a systematic review or meta-analysis with predefined search protocols. The abstract provides no primary human data, sample sizes, confidence intervals, or quantitative statistical comparisons.
Cited by
- supports Running a marathon in under two-and-a-half hours burns approximately 70% to 80% carbohydrates as fuel.