





Should you ingest fat during exercise?

Fat and carbohydrates are the main fuel sources during prolonged endurance exercise. Fat is the main fuel source during low-intensity exercise, while carbohydrates are the main fuel source during higher intensity exercise (Van Loon, 2001).

The depletion of carbohydrate stores in the muscle and liver is one of the main factors causing fatigue during prolonged exercise. However, these carbohydrate stores can be spared by the ingestion of carbohydrate (Stellingwerff, 2007).

Ideally, you would burn as much fat as possible during exercise, since you have very large fat stores (even lean athletes). Therefore, it could be speculated that the ingestion of fat would increase fat oxidation (burning fat as fuel) during exercise. Medium chain triglycerides (MCT) may be a good source of fat for his, as they are more easily oxidized compared to long chain triglycerides (LCT).

The current study investigated whether fat ingestion (MCT or LCT) together with carbohydrates increase fat oxidation rates during 60 minutes of cycling exercise compared to carbohydrates only.

Neither the MCT nor the LCT treatment increased fat oxidation rates compared to the carbohydrate treatment.

Therefore, nutritional recommendations during exercise for endurance athletes are entirely focused on carbohydrate ingestion.

In conclusion, fat ingested during exercise does not increase the use of fat as fuel and is therefore not necessary.

Study:

Ivy JL et al. Contribution of Medium and Long Chain Triglyceride Intake to Energy Metabolism During Prolonged Exercise. Int J Sports Med 1980

Go to the next infographic in the fat series:

Ketogenic diet impairs exercise performance?