How Fat-Burning Diets Change Exercise Fuel Use
Low carbohydrate high fat ketogenic diets on the exercise crossover point and glucose homeostasis
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists reviewed studies on low-carb high-fat (ketogenic) diets and found they completely change how the body uses fuel during exercise. Normally, during intense exercise, the body switches from burning fat to burning sugar (carbohydrates). But after adapting to a low-carb diet, athletes can keep burning fat even during very intense exercise.
Surprising Findings
Fat oxidation during high-intensity exercise (86% VO2max) was HIGHER than during moderate exercise
This directly contradicts the traditional crossover model which states fat oxidation is minimized above 85% VO2max. The study found the opposite - some subjects achieved their highest fat burning rates during very intense exercise.
Practical Takeaways
Consider metabolic health testing even if you're an athlete
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists reviewed studies on low-carb high-fat (ketogenic) diets and found they completely change how the body uses fuel during exercise. Normally, during intense exercise, the body switches from burning fat to burning sugar (carbohydrates). But after adapting to a low-carb diet, athletes can keep burning fat even during very intense exercise.
Surprising Findings
Fat oxidation during high-intensity exercise (86% VO2max) was HIGHER than during moderate exercise
This directly contradicts the traditional crossover model which states fat oxidation is minimized above 85% VO2max. The study found the opposite - some subjects achieved their highest fat burning rates during very intense exercise.
Practical Takeaways
Consider metabolic health testing even if you're an athlete
Publication
Journal
Frontiers in Physiology
Year
2023
Authors
T. Noakes, P. Prins, J. Volek, D. D'Agostino, A. Koutnik
Related Content
Claims (7)
When people switch to a low-carb, high-fat diet, their bodies can burn fat for energy during harder workouts that would normally require carbs, whereas on a normal diet this switch happens at easier exercise intensities.
About 30% of middle-aged competitive athletes eating a typical high-carb, low-fat diet have blood sugar levels that are higher than normal but not quite diabetic. When these athletes switch to a low-carb, high-fat diet, their blood sugar returns to normal levels.
Going on a low-carb, high-fat diet doesn't make runners slower, even though their muscles store less sugar for energy.
Athletes who follow low-carb high-fat diets can burn fat much faster during exercise—over 1.5 grams per minute—compared to athletes on regular high-carb diets who only burn 0.3 to 0.6 grams per minute.
When endurance athletes do high-intensity interval training at very hard effort (over 85% of their maximum oxygen capacity), they burn fat at extremely high rates - about 1.58 grams per minute on average, with some burning over 1.85 grams per minute. These are the highest fat-burning rates ever measured in people.