Is a High Fat Diet the Best for Endurance Athletes?

Submaximal Run Test

Volek also found that during a steady three-hour treadmill run at 65 percent of VO2 max pace, the fat-adapted athletes burned significantly more fat than the high carbohydrate diet athletes.

Numbers released from the study show that if the pace is 65 percent VO2 max, and if the runner consumes the typical high-carbohydrate-diet, roughly 40 percent of the fuel is coming from carbohydrates and 60 percent from fat.

If a high carbohydrate runner is cruising along at a pace that burns 500 calories per hour, he or she is burning around 200 calories per hour of carbohydrates and 300 calories of fat during exercise.

Comparatively, if a fat-adapted runner also burns 500 calories per hour, Volek's study states that he or she will only use 10 percent carbohydrates and 90 percent fat to fuel the run.

The high fat diet runner is burning roughly 50 calories per hour of carbohydrates and 450 calories of fat.

Our high carbohydrate diet runner is burning through carbohydrates at a rate of 200 calories per hour and our fat-adapted diet runner is only burning through 50 carbohydrate calories per hour. This is a huge difference.

Because we store only 1,300 to 2,000 calories of glycogen and fat stores are well in excess of 50,000 calories for most people, Volek's preliminary findings show that utilizing more fat to fuel exercise is beneficial for the endurance athlete.

More: The Top Race-Day Nutritional Tips

What We Don't Know

Athough Volek's study hasn't been entirely released, his conclusions raise a few questions. For example, do fat-adapted women burn more, less or the same amounts of fat during exercise as the men? How does this fueling plan work for athletes that need to sprint or put out intermittent bouts of high effort like road racers, mountain bikers and draft-legal triathletes?

Stay tuned as we learn more about the shifting paradigms of optimal athletic nutrition. Based on this research, you could soon be eating differently to fuel your body.

READ THIS NEXT: How to Fuel for Triathlon Success

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