Is Competition Won or Lost with Fat?

CEU Article Name: Efficacy of High-Fat Diets and Endurance

By: The NCCPT Education Staff

When people think of endurance events, they normally think of marathons, triathlons, cross-country races or events that last longer than three hours. The longer competition times would lend a coach, trainer or nutritionist to focus on the aerobic system. But in order to win an endurance event, one must be able to fuel the anaerobic system because that is really where the competition is won or lost.

Consider the example of a cycling race. A group of cyclists may travel at moderate intensities where fat can be utilized to fuel the aerobic system and meet energy demands. However, when it is time to climb a hill or sprint, the intensity increases dramatically and carbohydrate or glycogen utilization is required to meet the anaerobic system’s energy demands. So in theory, if glycogen was spared in the lower to moderate intensities and a dietary strategy of a high-fat diet would help spare the carbohydrates needed for the crucial higher intensities of the competition, then a high-fat diet would enhance overall endurance performance.

So should you up the fat?
Some studies conclude that short-term, high-fat diets may improve performance at 60-80 percent of VO2 max in endurance cyclist and runners (Williams, M. 2007, p. 185). Other studies have indicated that high-fat diets that maintained adequate carbohydrate levels increased endurance capacity when compared with low-fat diets (Williams, M. 2007, p. 185).
In contrast, long-term high-fat diets are not recommended. Other studies have found that although athletes could maintain high-intensity training with a high-fat diet, the perceived exertion was higher (Williams, M. 2007, p. 185). Other researchers found that despite the increased fat oxidation in high-fat diets, this strategy does not provide clear benefits to performance in endurance events (Williams, M. 2007, p. 185).

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Williams, M., (2007). Nutrition for Health, Fitness and Sport 9th edition, New York, NY, Mc-
Graw-Hill Companies, Inc.