University of Lynchburg DMSc Doctoral Project Assignment Repository

University of Lynchburg DMSc Doctoral Project Assignment Repository


Dr. Elyse Watkins



This paper intends to show that nutritional and training adaptations can improve the utilization of fat oxidation as a fuel source for endurance athletes and that it is an efficient source of fuel. Low carbohydrate availability is one of the key elements contributing to deteriorating exercise capacity during physically demanding sports. To increase endurance athletic performance with the limiting factor being carbohydrate availability, finding alternative efficient metabolic fuel sources could improve performance.


Advanced searches utilizing PubMed, MEDLINE, and Google scholar were performed. Key phrases for free fatty acid fuel source, carbohydrate, exercise physiology, fat adaptation in endurance exercise, and fat oxidation in exercise were utilized. Articles that were outside the scope of this paper were eliminated as well as those with animal subjects. Original research articles older than five years were eliminated as primary references. Manuscripts older than five years were used for historical purposes.


It does appear that free fatty acid can be used as an alternative fuel source, but only at sub-maximal efforts. The application in sport would be to improve athletic performance by instructing athletes how to effectively train and institute dietary regimens that utilize free fatty acids as an alternative/complementary fuel source and reduce glucose requirements.


Exercise capacity and performance are improved through endurance training by way of adaptations in skeletal muscle ,and increases in mitochondrial and capillary volume. These changes increase oxygen utilization and energy production which delays fatigue and prolongs aerobic performance. Carbohydrate is the primary fuel for aerobic exercise. A low carbohydrate, high fat diet increases reliance on fat as a fuel source for low to moderate intensity aerobic exercise. If utilized properly, this dietary strategy prolongs aerobic performance while decreasing reliance on endogenous carbohydrate stores and exogenous carbohydrate replenishment.

Key Words

Glucose, Carbohydrate, Free Fatty Acids, fat adaptation


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